THE COMET’S TALE

Newsletter of the Comet Section of the British Astronomical Association

Volume 9, No 2 (Issue 18), 2002 October

ASTEROIDS, COMETS AND METEORS 2002

Astronomers from all over the on this occasion he was doing of a comet brightening in this world gathered together in Berlin some casual star-gazing after a region. at the end of July for the triennial spell of bad weather. Fortunately Asteroids, Comets and Meteors he was able to recognise the Another development that was conference. The ACM series interloper and report his find. announced at the meeting is an began in 1983 in Uppsala, moving This was the first comet discovery exciting project called to the US in 1991 then alternating from Germany since 1946 and PanSTARRS, planned by the between the new and old world. drew a generous round of University of Hawaii. This will This year, in total there were 452 applause. search virtually all the northern astronomers from 34 countries, sky (except the pole) to with 22 from the UK, ranking us Also discovered during the th magnitude 24 (getting this faint in in 7 place well behind the USA conference was comet 2002 O6, less than a minute), three times a (105) and Germany (77). The which was the first real-time month. There may be four majority were professionals, discovery from the SOHO SWAN telescopes, each of 1.8-m aperture although there were a few instrument, which scans the sky in and capable of reaching the amateurs as well. the ultra-violet. Confirmation magnitude limit within a minute over a 3° field. Each frame will be around a billion pixels giving a huge flow of data at around 2 Tb a night. There will be a NEO (Near Earth Object) in every other frame and it may discover 100 comets a month, with the chance of seeing some interstellar ones. Comets will be confirmed in real time as the resolution is around 0.6", far better than existing programmes. It will discover around 10,000 KBOs (Kuiper Belt Objects) in the first year and 600,000 asteroids a night. It will put the supernova searchers out of business too, as it will detect new objects as well as moving objects and find perhaps 100,000 a year. The project is funded to the tune of $40M and is likely to be on line within a few years. The problem Sebastian Hoenig, Maik Meyer and Brian from ground based observers will be following up all the Marsden discuss SOHO comets in the made this only the second SOHO objects it discovers and providing Stadthall of the Technical University of discovered comet to be observed linkages between the moving Berlin. from the ground. This discovery objects. perhaps sounds the death knell for Continued on page 5 Many exciting developments were amateur comet discoveries. Contents reported, including the discovery Between the SOHO LASCO and of comet 2002 O4 (Hoenig), SWAN instruments and LINEAR Comet Section contacts 2 which was discovered by and future search programmes Section news 2 Sebastian Hoenig from there is little sky left for the Tales from the past 3 Heidelberg on July 22. Full moon amateur to search. There is Professional tales 3 intervened and it wasn't until July perhaps a small band running ACM2002 (Cont) 5 29 that the discovery was finally about 8° north of the ecliptic to Review of observations 13 confirmed. It was an accidental around 50° from the Sun in the Edgar Wilson Award 23 discovery, and although Sebastian evening sky, which SWAN has done some comet searching, cannot see, and there is a chance Predictions for 2003 23 BAA COMET SECTION NEWSLETTER 2 THE COMET’S TALE

Comet Section contacts

Director: Jonathan Shanklin, 11 City Road, CAMBRIDGE. CB1 1DP, England. Phone: (+44) (0)1223 571250 (H) or (+44) (0)1223 221400 (W) Fax: (+44) (0)1223 221279 (W) or (+44) (0) 1223 571250 (H) E-Mail: [email protected] or [email protected] Antarctic e-mail: [email protected] WWW page : http://www.ast.cam.ac.uk/~jds/

Assistant Director (Observations): Guy Hurst, 16 Westminster Close, Kempshott Rise, BASINGSTOKE, Hampshire. (and also Editor of RG22 4PP, England. The Astronomer magazine) Phone & Fax: (+44) (0)1256 471074 E-Mail: [email protected] or [email protected]

CCD Advisor: Nick James, 11 Tavistock Road, CHELMSFORD, Essex. CM1 5JL, England. Phone: (+44) (0)1245 354366 E-mail: [email protected]

Photographic Advisor: Michael Hendrie, Overbury, 33 Lexden Road, West Bergholt, COLCHESTER, Essex, CO6 3BX, England Phone: (+44) (0)1206 240021

Subscription to the Section newsletter costs £5 for two years, extended to three years for members who contribute to the work of the Section in any way, for example by submitting observations or articles. Renewals should be sent to the Director and cheques made payable to the BAA. Those due to renew should receive a reminder with this mailing.

Section News from the Director

Dear Section member, Encke has not changed present the lecture. There will be significantly in the last 50 years. further details about this meeting At the end of July I attended the in the next issue, on the Section Asteroids, Comets and Meteors There are a couple more comet web page and in BAA Circulars. meeting in Berlin. This event saw meetings coming up. The Royal a large gathering of comet Astronomical Society has a I have been kept very busy over specialists and a large part of this meeting on December 13 devoted the summer with a variety of issue is given over to my report of to "Cometary Science at the activities and still have some the meeting. One key message Launch of Rosetta". The meeting correspondence to catch up with. from the meeting is that there is runs from 10:30 to 15:30 and If you are waiting to hear from likely to be a rapid growth in takes place in the Geological me, please accept my apologies dedicated search telescopes. I Society Lecture Theatre in and I hope to respond soon. fear that the day of the amateur Burlington House. The organisers visual comet discovery may have give this summary: Recent years I will be visiting Antarctica again passed, unless SOHO fails before have seen marked advances in the from mid February to early April, a replacement is in orbit. There is study of comets, largely through so the next issue of The Comet's still however much useful work ground-based observations of Tale may be a little delayed from that the amateur can carry out. Hyakutake and Hale-Bopp, and its nominal issue month of April. CCD observers can provide in-situ measurements of I will be in limited email contact follow-up astrometry and Hyakutake and Borrelly. The (see address above - no pictures confirmation of the cometary imminent launch of the Rosetta please), but will be unable to nature of newly discovered mission is taken as an opportunity update the Section web pages. objects. Stephen Laurie recently to review progress made in this Whilst away I should be able to made observations within 24 field, and to discuss the questions begin work on the Journal papers hours of an object being posted on and challenges to be addressed in covering the comets of 1999 and the NEO confirmation page. the future. The meeting will cover 2000. Imagery also allows study of all aspects of cometary science, morphological changes in the from studies of the nucleus, dust, The visit is to set up our part of a coma and tail, and these are often and coma, to comets' interactions big European project to used by professionals. Visual with the solar wind." Following investigate the ozone layer. observers can continue traditional this, there is a pro-am discussion Although we know the basic magnitude estimation as this meeting on 2003 May 10, theory of how the ozone layer is allows long period comparison of provisionally in Liverpool. The destroyed, there is much fine returns of periodic comets. BAA meeting will include the first detail still to discover. Several observations show that the George Alcock memorial lecture Antarctic stations are participating absolute magnitude of comet and I am delighted to say that in the experiment, where balloons Brian Marsden has agreed to carrying ozone measuring sensors BAA COMET SECTION NEWSLETTER 2000 October 3 will be launched in carefully from: Jose Aguiar, Alexandre which currently do not send synchronised sequence to measure Amorim, Alexander Baransky, observations to the BAA. the same air mass as it passes over Sandro Baroni, Nicolas Biver, each station. We hope to discover Reinder Bouma, Nicholas Brown, Comets under observation were: which of several competing Jose Carvajal, Tim Cooper, 7P/Pons-Winnecke, 19P/Borrelly, variations of the theory give the Matyas Csukas, Mike Feist, 44P/Reinmuth, 46P/Wirtanen, best match with observation. Rafael Ferrando, Sergio Foglia, 51P/Harrington, 65P/Gunn, Stephen Getliffe, Antonio 77P/Longmore, 1999 U4 Since the last newsletter Giambersio, Guus Gilein, Bjorn (Catalina-Skiff), 1999 Y1 observations or contributions have Granslo, Roberto Haver, Michael (LINEAR), 2000 SV74 been received from the following Jager, Andreas Kammerer, Heinz (LINEAR), 2000 WM1 BAA members: James Abbott, Kerner, Attila Kosa-Kiss, Gary (LINEAR), 2001 A2 (LINEAR), Sally Beaumont, Neil Bone, Kronk, Martin Lehky, Rolando 2001 B2 (NEAT), 2001 HT50 Owen Brazell, Denis Buczynski, Ligustri, Pepe Manteca, Michael (LINEAR-NEAT), 2001 K5 Roger Dymock, Kenelm England, Mattiazzo, Maik Meyer, Antonio (LINEAR), 2001 MD7 Len Entwisle, James Fraser, Milani, Andrew Pearce, Maciej (LINEAR), 2001 N2 (LINEAR), Mario Frassatti, Maurice Gavin, Reszelski, Tony Scarmato, Hirita 2001 OG108 (LONEOS), 2001 Massimo Giuntoli, Peter Grego, Sato, Carlos Segarro, Giovanni Q2 (Petriew), 2001 Q5 (LINEAR- Werner Hasubick, Guy Hurst, Sostero, Graham Wolf and Seiichi NEAT), 2001 Q6 (NEAT), 2001 Nick James, Geoffrey Johnstone, Yoshida (apologies for any errors R1 (LONEOS), 2001 R6 Gordon MacLeod, Brian or omissions). Without these (LINEAR-Skiff), 2001 TU80 Manning, Steve Martin, Cliff contributions it would be (LINEAR-NEAT), 2001 X1 Meredith, Martin Mobberley, impossible to produce the (LINEAR), 2002 C1 (Ikeya- Gabriel Oksa, Roy Panther, Robin comprehensive light curves that Zhang) and 2002 E2 (Snyder- Scagell, Jonathan Shanklin, David appear in each issue of The Murakami), 2002 O4 (Hoenig), Strange, Melvyn Taylor, John Comet’s Tale. I would welcome 2002 O6 (SWAN). Vetterlein, Alex Vincent and observations from any groups Graeme Waddington and also Jonathan Shanklin Tales from the Past

This section gives a few excerpts cloudy and foggy. His from past RAS Monthly Notices 100 Years Ago: In April BAA observations continued until and BAA Journals. Member William R Brooks wrote August 2. This was his first about his discovery of comet 1902 evening find after 15 years of 150 Years Ago: Professor Secchi G1 (Brooks). This was his 23rd searching and was made using a discovered a small comet in comet, and the 12th from Geneva, 90 mm Wray. [I visited Thames Gemini on August 25, which was New York. The comet Section on 1998 September 18 - 19 and suspected to be one of the parts of annual report for the year notes whilst there observed comet 1998 Biela's comet, and on September that there were now 15 Members P1. Skies were still very dark and 15 he discovered the other of the Section. It includes a report clear, but must have been even portion. It was very faint, without from John Grigg, of Thames, New better a hundred years earlier. At nucleus, and of a long oval shape, Zealand, of his discovery of a the time I hadn't even realised the the point turned to the Sun. The comet on July 22 (26P/Grigg- connection with John Grigg!] larger and brighter portion had not Skjellerup). As he was preparing the same shape as when seen on to note its position a fire broke out 50 Years Ago: The Section August 25: it was altogether in his neighbourhood and his annual report notes that eight irregular and with two very feeble work for the evening ceased! He comets were observed during the brushes. The centre was more confirmed the object the next session and lists 28 observers. luminous than the edges, but there evening, though was still was no nucleus. doubtful, as the weather was Professional Tales

SOHO Comet 500 Discovered guessing that date and time for the discoveries have come from Paal Brekke, NASA/ESA Press SOHO-500. Her prediction was amateur comet hunters around the release too early by only 103 minutes. world watching the freely available SOHO images on the A small object spotted by Rainer The LASCO coronagraph on web. Kracht of Elmshorn in Germany, SOHO, designed for seeing in an image from SOHO received outbursts from the Sun, uses a The biggest tallies have come via the Internet, has been mask to block the bright rays from from Mike Oates in England, officially confirmed as Comet the visible surface. It monitors a Rainer Kracht in Germany and 2002 P3 (SOHO). It is the 500th large volume of surrounding Xavier Leprette in France. They comet discovered with the ESA- space, and as a result it became went back over pictures from NASA solar spacecraft and it the most prolific discoverer of 1996-99 and found dozens of made its closest approach to the comets in the history of comets that the professionals had Sun at 16:05 Universal Time on astronomy. Most of them are overlooked. Kracht, a Monday, 12 August. Diane small sungrazer comets that burn mathematics, physics, computer McElhiney of won a contest run up completely in the Sun's hot science and astronomy teacher at by the SOHO science team for atmosphere. More than 75% of the Kooperative Gesamtschule BAA COMET SECTION NEWSLETTER 4 THE COMET'S TALE

Elmshorn in Elmshorn, Germany Roeser Observatory in A system of comets called has discovered 63 comets since Luxembourg and the Cote de "sungrazers," named for their August 2001 with the help of Meuse Observatory in France. orbit that closely brushes the Sun, SOHO data and images. Mike The camera will allow Dawson to reveals important clues about how Oates from Manchester, England observe objects as faint as 21st these bodies break up. Most is the highest-scoring discoverer magnitude. sungrazing comets are tiny -- the of comets ever, with 136 to his smallest could be less than 10 name, while Rainer Kracht has Richard Kowalski of Florida meters (30 feet) across -- and discovered 63. founded the Minor Planet Mailing move in a highway-like formation List four years ago to provide an of comets that pass near the Sun Amateurs Win NEO Grants opportunity for minor-planet and disintegrate. Vanessa Thomas Astronomy.com observers around the world to © 1996-2002 Kalmbach communicate with each other. In Dr. Zdenek Sekanina, senior Publishing Co. the past, Kowalski has spent his research scientist at JPL, reports own money to maintain the list, in the September 10 issue of the It seems we've been hearing a lot and will receive a $900 grant to Astrophysical Journal that many more reports of asteroids and support the list and related sungrazer comets arrive at the Sun comets zipping past our planet websites for the next three years. in clusters and on parallel paths. lately. Has Earth recently entered He emphasizes that such tiny a more populated space, Amateur astronomer James fragments would have increasing the number of McGaha of Tucson, Arizona, will disintegrated if they had come so encounters with these smaller use $10,000 to automate the 24- close to the Sun on an earlier trip. neighbors? Nope. It's just that we inch (62-centimeter) telescope at Therefore, the parents of these humans recently have become his Grasslands Observatory 55 tiny sungrazers must have broken more aware of our immediate miles from his home. This will up after their previous encounter cosmic surroundings and have improve the telescope's efficiency with the Sun and continued to begun to pay more attention to in the NEO observations it makes. break up far from the Sun on their these near-Earth objects (NEOs). journey through the solar system. Roy Tucker, also of Tucson, To improve our awareness and currently has three telescope- Sekanina's sungrazer studies understanding of these frequent camera systems observing NEOs, challenge an earlier theory that passers-by (and potential but the resulting data is more than the only place these comets break impactors), the Planetary Society he can handle. Tucker will up is very close to the Sun, as the established the Shoemaker Near- receive $2,950 for software and strong pull of its gravity cracked Earth Object Grant program in computer equipment to distribute their loosely piled chunks of dust 1997. Named after the late his observations to other local and ice. The gradual, continuing planetary geologist Eugene amateurs who can help reduce and fragmentation gives birth to all Shoemaker (who studied analyze the data. the sungrazers, the most asteroids, comets, and their outstanding examples of splitting impacts with the larger bodies of The five winners were selected by comets. the solar system), the grant helps an international advisory group both amateur and professional from 37 proposals received from "Astronomers never before astronomers enhance their own 13 countries. "With so many realized that there could be a NEO projects. highly qualified proposals, the fairly orderly pattern in breaking selection committee's choice was up, so that one comet cascades This year, the Planetary Society is a difficult one," states the into large families of smaller awarding a total of $28,290 to Planetary Society's announcement comets, and that this process five deserving NEO programs on of this year's winners. could be an important part of a three continents. comet's natural life cycle," The Planetary Society is not yet Sekanina said. John Broughton of Reedy Creek accepting applications for the next Observatory in Queensland, round of Shoemaker NEO Grants, Sungrazers are not the only Australia, is an active observer of but you can watch for updates or comets that can break up far from NEOs and has discovered several learn more about the grant the Sun. Sekanina points to new asteroids, including those named program from the Society's observations of comet 57P/du after the Beatles, Elvis Presley, website. Toit-Neujmin-Delporte, whose Buddy Holly, the Beegees, and fragmentation has led to the Brian Wilson. Broughton will Comets break up far and near formation of a similar, though less receive $8,140 from the Planetary NASA News prominent, highway of tiny Society to buy an Apogee CCD comets. All fragments separated camera to use on a new computer- Some comets may break apart from the comet beyond the orbit controlled 18-inch (46-centimeter) over and over again in the farthest of Mars. telescope, which will conduct reaches of the solar system, follow-up observations of fast- challenging a theory that comets Images taken by the European moving NEOs and those not break up only occasionally and Space Agency's and NASA's visible from the Northern not too far from the Sun, says a Solar and Heliospheric Hemisphere. researcher from NASA's Jet Observatory have shown the Propulsion Laboratory (JPL), many tiny sungrazing comets. Amateur NEO observer Matt Pasadena, Calif. Nearly seven years' worth of Dawson will also purchase a new images from the solar observatory Apogee CCD camera to use at the revealed more than 400 BAA COMET SECTION NEWSLETTER 2000 October 5 sungrazers in the Sun's immediate comets the size of the ones the group comets was essentially neighborhood. Sekanina observatory detected. [However a random, and they do not form estimates that currently there may paper at the ACM suggested that clusters.] be as many as 200,000 sungrazer the distribution of SOHO Kreutz Asteroids, Comets and Meteors 2002

Continued from page 1 made the lecture and hotel rooms very stuffy. There were many The Kuiper belt is becoming The following précis gives a pleasant pavement restaurants. better understood, but there are flavour of the comet science Sight-seeing highlights included roughly the same number of these discussed at the meeting. It is the Tiergarten, Schloss objects as there were main belt from my notes and reflects what I Charlottenberg, the Pergamon asteroids in 1900. A plot of the heard and have interpreted from Museum (particularly the Ishtar distant objects clearly shows the speakers' talks and posters and gate) and a river cruise, though classic KBOs, plutinos (and may not be what they intended! the famed Brandenburg Gate was clearly Pluto is just a large one of Generally I have brought together under wraps. The next meeting these and therefore NOT the ninth themes and do not always credit will be 2005 in Rio de Janeiro, planet), SDOs (scattered disc specific speakers with the followed by 2008 in Baltimore. objects) and Centaurs. Smaller discoveries, nor should it be In the meantime there is a meeting bodies a likely to predominate. assumed that a named speaker in London on December 13 to KBOs tend to be neutral to red in made all the remarks in that discuss comets prior to the colour whereas comets are section. In some cases I make Rossetta encounter and I am significantly bluer and similar to comments, though I have avoided organising a pro-am meeting on Trojan asteroids. Comets have no putting some that could be made, comets and meteors for 2003 May "ultra-red" material because as into print! Invited talks were 10. Brian Marsden has agreed to soon as they pass Jupiter/Saturn normally 30 minutes, but other give the inaugural 'George Alcock mantling by ejecta is faster than talks were only 10 minutes and Memorial Lecture' at this meeting. the dynamical lifetime. KBOs speakers often spent most of the and Centaurs are therefore more time introducing their paper and Comets diverse than comets because of not presenting their conclusions. this mantling. Comet light curves Abstracts of papers presented at David Jewitt (U of Hawaii) are generally more extreme than the meeting are at kicked off proceedings with a talk KBOs and Centaurs, by up to 2 http://berlinadmin.dlr.de/SGF/acm entitled 'From Kuiper Belt to magnitudes and are perhaps more 2002/. In order to encourage Cometary Nucleus'. Comets are elongated than simple collisional participants to stay to the poster collisionally produced in the fragments. Comets are very dark sessions the organisers laid on Kuiper Belt (KB) and are compared to asteroids, though German beer, wine and snacks for modified on the journey inward. probably 10% of NEOs are dead us to sample! They may reside in the KB for 109 comets. Comets are less dense (at - 1010 years and only spend 107 as 500 gm/cc) compared to KBOs Some 'elder statesmen' were often a comet and perhaps 4 x 105 as a (1500) implying they are very didactic in their views and Jupiter Family Comet (JFC). The porous, though even KBOs are unknowledgeable outside their thermal conduction time scale, tc, pretty porous. Comets are own sphere, and were often given is approximately r2/k and for probably weakly bonded undue deference. The general bodies with r larger than 5 km this collisional rubble piles, with scientific conference system tends is longer than the inward diffusion perhaps more 50% pore space. to encourage mainstream views, time, and for bodies larger than 2 with little chance for km it is longer than their lifetime There are no KBOs with low e individualistic ideas. Another as a JFC. This means that comets and with perihelion at 50 AU. point is that professional are out of thermal equilibrium and This possibly marks the edge of astronomers often get only a few are therefore "ice bombs". The the primordial solar nebula, or it nights observing at widely spaced sublimation life time is about the could reflect stellar encounters or times and as a consequence dynamical life time for bodies a trans-Neptunian planet. A appear to underestimate their with r around 40 km so JFCs must stellar encounter with a 1/3 solar observational errors. die by sublimating away or mass star, passing at 200 AU with Compilations from several growing a mantle, so there must an inclination of 30° provides the sources often showed variation be dead comets. best fit and can explain the SDOs. outside the error bars, and many 95P/Chiron started a new outburst did not even give error bars. It Comets spin up much faster than in 2000/01, which might last until was noticeable that many papers their dynamical lifetime thanks to 2003. Since 1965 its absolute V from eastern European or Russian the Yarkovsky effect. This can magnitude has varied between 5.1 authors used old data from the modify minor body orbits and and 7.3 and is currently around 6. 1970s and 80s. rotation rates through re-radiation of sunlight and was invoked by The Space Telescope has been Berlin was a light airy city, with many theorists to explain the used to observe comet nuclei and lots of trees, wide pavements and inward migration of some orbits when combined with data from comparatively little traffic. The and the spin up and disintegration ISO (infra-red satellite) it is S-bahn (overground train) system of some nuclei. Duncan Steel possible to make deductions about was very efficient and cheap, with suggested that comets could break their size and albedo. clean carriages and plenty of up through Joule heating due to a 10P/Tempel is quite a large space. For most of the conference current flowing through a object, whilst 45P/Honda-Mrkos- it was very hot (30°+), which conducting coma. Pajdusakova is the smallest. BAA COMET SECTION NEWSLETTER 6 THE COMET'S TALE

55P/Tempel-Tuttle has 5% primary jet near the pole. This and 45 - 70° from the Sun to 20m albedo, whilst 19P/Borrelly is the location implies that seasonal using a 15cm f6 Maksutov. It most elongated. There are large effects should be present, with would have 2" astrometric numbers of small objects with peak sublimation from 2001 precision. It would observe radii less than a km. SPC (Short August to mid-September, comets closer to the Sun than Period Comets) are not followed by a rapid switch off. present search programmes and significantly bluer than KBOs. There may be a secondary jet in would search for Kreutz comets. For small SPC cometary activity the opposite hemisphere. The In some eclipse geometries it may cover 100% of the surface. mass of the comet is around 1.8 x could search even closer to the The large diversity in colour 1013 Kg, with dimensions 4 x 4 x Sun. reflects primordial variation. 8 km, giving a density of 0.27 that Colour studies provide the first of water, although it could be The Stardust spacecraft encounter evidence for a physical link from higher in the range 0.29 - 0.83. It with comet 81P/Wild (the pros KBOs to dead comets, and there rotates with a period of 25±0.5 were not very good at using the is a colour shift over dynamical hours. There was a steep fall off correct identifications for comets) evolution. Comments made after in gas production (a factor of 20 - takes place on the same day as the talks include that just because 30x) between 1.36 and 1.89 AU. launch of the Deep Impact things are the same colour doesn't A polar source is continuously in spacecraft. Stardust is a dust mean that they are the same. For sunlight during September, but return mission but will provide example everything in a three months later is in darkness imagery at 10 - 20 metres greengrocers that is green is not and will remain in darkness for resolution. Unfortunately the necessarily an apple. A rubble the next six years. The source has comet is at only 33° elongation at pile is what you get when you a total area of around 3.5 km2, the time of the encounter, but all drop a load of rocks out of the about 4% of the total surface area. ground based observations will be back of a truck. This is not the New features seen in DS1 images of use. Contour will explore the same as a gravitational aggregate, include hemispheric jet bases and evolutionary diversity of comets which is what a dynamicist means loop features. Dust impacts were and has imaging better than 5 by a rubble pile. only detected near closest metres. Deep Impact will approach, with the nominal size of investigate the interior of the At the DS1 encounter with the particles 1.3mm. There were nucleus ("a crude experiment but 19P/Borrelly the coma had less some double hits, implying a interesting") and can image to than 1% of the intensity of the separation between particles of around 1.5 metres; it will also nucleus. The physical properties 2.5 - 25 metres. The dust is very benefit from ground based are generally similar to asteroids. red, implying large grains. There observations. They don't really The overall albedo was 2.9%, is evidence for fragmentation of know what sort of crater to which is within the error bars for icy particles (10 - 100 micron) expect. A strong surface gives a that measured for 1P/Halley, but it near the nucleus. Modelling small crater with diameter to varied between 1% and 5%, with shows that the comet can form a depth ratio of 3:1 and an ejecta two peaks in the distribution. A stable crust, which is thicker at cone that detaches. A porous few asteroids have similarly low the poles. surface fives a small deep crater albedos, including NEOs but and if the surface is weak it will Iapetus or the rings of Uranus are The 2MASS survey has detected excavate material to give a 60 - the best match. The bond albedo 265 comets of which 117 were 240 m crater with a ratio of 4:1, is only 0.9%, so the surface is a periodic. It found prediscovery which is what the team is working good absorber of energy, which is images of a couple of comets. on. No missions will measure a why it is hot. There is evidence Association is by position within comet's mass before Rossetta. that the regolith is 'fluffier' than a relatively wide window, which There are no planned missions to any other body. There are two gives significant false detections an OCC (Oort Cloud Comet), terrains - roughly 50/50 for asteroids. It also implies that though Contour could be targeted 'desiccated' and 'smooth', although there may be undiscovered comets at one. An OCC is one that is the 'smooth' (or mottled) terrain is present in the data-set. The ISO making its first trip into the inner rougher at the pixel scale and survey data is also now publicly solar system and which has a perhaps reflects ponding of available and this may hold Tisserand invariant less than 2; material. The surface is probably previously undiscovered the Tisserand invariant is a covered in 'native' particles, ie observations of comets and measure of an object's comet dust. Mottled terrain asteroids. gravitational interaction with shows dark areas, which may be LONEOS/LINEAR/NEAT/Catali Jupiter. There is a proposal for a the sites of former jets, as the na don't search below -30° or comet surface sample return over present jets map back to dark above 80° or closer than 6 hours the next decade, though cryogenic regions. There is some evidence from the Sun, though occasional storage and return of a sample is a that as the comet outgasses the special searches go to 4 hours. long way off. surface gets darker, so these areas LONEOS avoids the milky way may be older. Geology includes and concentrates on the ecliptic. Olivier Groussin and Philippe dark spots, circular depressions, Lamy suggest that there is a rapid ridges and fractures, but no Another possible space mission is increase in water production in impact craters. Around 6- 8% of NESS (Near-Earth Space comet 46P/Wirtanen prior to the surface was active. The upper Surveillance), which is being perihelion, with the active fraction layer of refractory material was studied by the Canadian Space of the surface increasing from hot at 300 K, with no sign of Agency. This is a small satellite 10% to 85% in 10 days when the water ice. The rotation pole was in sun-synchronous earth orbit. It comet is at around 1.5 AU. The located at 214° -5°, with the would scan ±20° from the ecliptic albedo is less than 10%. After BAA COMET SECTION NEWSLETTER 2000 October 7 perihelion the activity again latitude of perihelion (50°) than Daily summary pages are on the reduces to 10%. They suggest the other two groups (10°) and the web at that a one metre thick mantle Marsden group has a greater http://sohowww/data/summary/sw blowing off causes the change. inclination than the Kracht group. an/swan-images.html Magnitudes The paper is based on a few data There may be a fourth group are accurate to around ±1 and points measured in 1997 and comprising of three members so positions to around 15'. Comets could equally be another example far (2000 Q1, 2000 Y6, 2000 Y7), can be seen down to 11 - 12 of under-estimation of and clearly most SOHO comets magnitude. 2000 S5 was observational errors. Another are members of groups. In discovered during a second paper suggested that both 46P and answer to a question on whether assessment of the Lyman alpha Hale-Bopp need to have a low the groups are uniform in time, images using a neural net system matrix heat conductivity and large Brian replied that the objects look to detect moving images. It might active areas to explain the asteroidal and the search is have disintegrated after perihelion measured molecular fluxes. perhaps not yet complete. and is best searched for on its inbound leg. There is a chance A dust trail from 22P/Kopff has Michael Kueppers et al looked at that an amateur astronomer may recently been detected. It the possibility of detecting have recorded it on a photograph comprises of large (cm sized), cometary ions from Kreutz or image. The assessment dark (1% albedo) particles similar fragments as they pass the earth. suggested that search programmes to the parent comet KBOs and The maximum size of the Kreutz were missing around 5% of the Centaurs. fragments is ten to around 50 brightest comets. SWAN has metres for a solid body observed comets 2P, 19P, 21P, The SOHO C3 LASCO sublimating completely. If tidal 41P, 45P, 46P, 55P, 73P, 81P, coronagraph has a 77.6mm f9.3 splitting occurs (such as seen in 96P, 103P, 141P, 1995 O1, 1995 lens, which allows a 1' resolution Ikeya-Seki) they could be as large Y1, 1996 B1, 1996 B2, 1996 N1, and can observe out to 15° from as a few hundred metres. From a 1996 Q1, 1997 J2, 1997 K2, 1997 the Sun. Comet 96P/Machholz sample of 386 SOHO Kreutz N1, 1997 O1, 1997 Q1, 1997 T1, was observed over a phase angle comets there is no convincing 1998 H1, 1998 J1, 1999 H1, 1999 from 160 - 114°, though incoming evidence for the non-random J3, 1999 N2, 1999 S4, 1999 T1, observations were overexposed. distribution of perihelia times on 2000 S5, 2000 W1, 2000 WM1, Klaus Jockers et al suggest that small timescales, as proposed by 2001 A2 and 2001 Q2. the comet shows a phase effect Sekanina (ie comet pairs). The when very close to perihelion. Earth could pass through a When comets with semi-major The polarisation curve fits quite disrupted plasma tail in axes greater than 100 AU are sub- well to the expected curve, but September/early October, but the divided into groups of different appears to be a little higher. The chance is only around 2% a year dynamical age Fernandez found tail is dominated by dust given the observed comet that there were significant emission. Unfortunately the frequency. differences in inclination between speaker ran out of time to present the afe groups. The ratio of his conclusions. Hiroshi Kimura (Doug Biesecker prograde to retrograde orbits also was a co author) began his talk varies with 1/aorig. A plot of 1/aorig and by showing a nice painting of shows two peaks - one from the comet 1882 R1 by Ichigoro inner Oort Cloud and one from Ogawa and said that the tail was the outer Oort Cloud, which has a interpreted as an omen of a rich boundary at around 3 x 109 AU. harvest. Dust grains include a Comets from the outer cloud are major population of sub micron all new, but the inner ones have to silicate grains, in aggregates traverse the Jupiter/Saturn region containing more olivine than as Centaurs (because the change pyroxene. Pyroxene sublimes at in energy is proportionately around 5 solar radii, whereas smaller), which is why there is an olivine sublimes at around 10 excess of retrograde orbits in this Sebastian Hoenig, Maik Meyer and Brian solar radii. Kreutz group comets class. The excess of prograde Marsden at ACM2002 fade as they approach closer to the orbits in the outer cloud could be Sun, with two groups of light due to too small a sample, or Brian Marsden reviewed orbit curves. One begins to fade at 11 - because the distribution reflects computations for the SOHO 12 solar radii, with perhaps some memory of the original comets. Some comets were another weaker group at 7 - 8 formation orbit. Another paper clearly not members of the Kreutz radii. There are perhaps sub- suggested that comet aphelia are group, and as numbers increased peaks at 11.2 and 12.3 radii, aligned along a great circle, which close pairs began to appear, which reflect different dust implies an impulsive component followed by members wider properties - amorphous and to the flux. There is also a pattern displaced in time. These become crystalline olivine. There is no of orbital element correlations. known as members of the Meyer, correlation with the comet orbits. This is unlikely to be caused by Marsden and Kracht groups, observational bias (ie selection though all three groups have a A poster by Teemu Makinen et al effects or bad data). The lack of similar longitude of perihelion describing the discovery of comet comets along the galactic equator (~100°), which is similar to that 2000 S5 had a post-it note added is due to galactic forces, but there of the daytime Arietids, during the meeting noting that are two peaks in longitude which 96P/Machholz and the Masayuki Suzuki had made a are not expected from the galactic Quadrantids. This is odd! The possible real-time discovery. tide. Of 27 new orbits between Meyer group have a higher BAA COMET SECTION NEWSLETTER 8 THE COMET'S TALE the 11th and 14th catalogues 9 are a thin layer of crystalline ice, over between there is reactive fluid in this distribution. The comets in a mixed layer of amorphous and dynamics, but no solar wind or the great circle distribution are crystalline ice then a pristine magnetic effects. Solar visible more tightly bound. The most nucleus. This structure is quite radiation initiates sublimation likely cause is a Jovian sized different to that of JFCs. LPCs from the nucleus. To model what companion in the Oort Cloud. experience strong thermal stress goes on a multi-fluid approach close to the surface. including neutrals, ions, electrons, Some recent research on cometary H, H2, dust etc is adopted and the volatiles presented by Michael A lot of species have been continuity equations are solved Mumma uses measurement of measured in high resolution separately. The most important several parent species within a spectra of 2000 WM1. These terms are the inhomogenous ones, short space of time. Eight of nine include C2, NH2, CN, C3, CO, such as chemistry, mass + - + + - comets studied have similar H2O , CH , CO , CH and C2 . {condensation, evaporation, etc}, chemistry, though 1999 S4 is an The ratio of C12/C13 is close to the momentum and energy that are exception. CO shows evidence terrestrial, but that of N14/N15 is related to sources and sinks and for a distributed source in Hale- only half, though comparable to are particularly affected by He Bopp and varies by a factor of 20 that in Hale-Bopp. The outbursts and H. The near nucleus region is between different comets. of 2001 A2, which is a gas rich very asymmetric, because of jets Compared to water most comets comet of the Halley class (or etc, but is approximately show about 2% methanol and possibly a water poor Borrelly symmetric by 100 km. All this is 0.6% ethene. The studies show type) [note that chemists use a solved and velocity & temperature that the Oort cloud does contain different naming convention to the profiles are derived that generally comets that are chemically dynamicists], were associated agree with the observations. diverse, with 2/3 forming beyond with fragmentation, except the Parent species generally follow a 30 AU and the remaining third one on July 12. CN, CH, CH+, 1/r2 distribution, but daughter forming between 5 and 30 AU. C3, C2, NH2, and O[I] were species have various patterns as Polarisation measurements help detected in its spectra. P/2001 Q2 the parents are broken down by enhance dust features, eg shells in is also a Halley type comet. The solar ultra-violet radiation to give Hale-Bopp. There are three ortho/para spin temperature for many daughters. There are classes of comet: low polarisation, 1P, 1995 O1, 1999 S4 and 2001 differences between what happens high polarisation and Hale-Bopp. A2 is around 28K, suggesting an when the sun is active and when it What causes the difference is not origin in the Saturn/Uranus is quiet. Radiative transfer in the known. Long term monitoring of region, whilst that for 103P is coma is complex, with factors Hale-Bopp from 7 AU on the way around 35K. Complex chemicals such as optical depth and in, through perihelion and out to ('pre-biotic') can form in comets. shadowing playing a part. 14 AU shows significant short- 19P is in the C2 depleted class of Extreme UV penetrates into the term variation in molecular comets. The source for C2 may be innermost region. Water species, especially CO. The C2H6 or ethane for comets dominates at distances less than transition from a CO to H2O depleted in C2, whereas CH3C2H about 2 - 3 AU from the Sun, with dominated coma occurs between 3 or CH2CCH2 may be the source carbon monoxide at greater and 4 AU. At large solar for C3, although another distances. Gas phase reactions distances water production rates possibility is C3H8. vary in importance with distance depend on a complex combination from the Sun and from the of seasons, spin state, r and the Many groups had observed 2002 nucleus. Close to the nucleus thermal properties of the nucleus. C1. NH3 had been detected for electrons are coupled to water CO production rates depend only the first time in the infrared, at a through inelastic collisions, but on r and it doesn't sublimate from few x 1026 in the month after further out they decouple giving a great depths, so the nucleus may perihelion. This was only 0.7% steep rise in electron temperature 4 be very inhomogeneous. that of water. C2H4 (di- to 10 K. Dust gives distributed Generally production was higher acetelyne), only observable in the gas sources and can lead to after T, but it modelling suggests infrared, was also detected at heating of gas through radiative that it depends on seasonal around 0.05% water, with HC3N heating. Generally even the best effects. A lower limit for the also detected. A sodium tail was models don't give a brilliant fit to nuclear radius is 13 km. The seen. CO was much higher in the observations and it seemed rotation axis was constant 1999 T1 at 13% than in 2001 A2 that the model was more between 1995 and 2002. There or 2000 WM1 at <1%. The important than reality, with one were at least four active regions preliminary estimate for 2002 C1 not even incorporating a dusty on Hale-Bopp, with a was 8% of water. The presence of crust. continuously active northern fan. a hot component at 300 - 500 K Some outbursts were in a 'palm- suggests a CO2 source. Water is difficult to observe from tree' pattern and others included the ground, but the Odin satellite 'boulder spitting' as mini-comets. Daniel Boice reviewed processes can measure it from space using Small condensations were seen in in the coma. At 1 AU the inner emissions at around 550 GHz and the coma of 1996 B2 over a coma is dominated by collisions has observed comets 1999 H1, period of around 20 days, which in a moderately active comet. 2001 A2, 2000 WM1, 2002 C1 were possibly mini comae around The mean free path is around a and 19P. Comet 1999 H1 (Lee) icy fragments between 5 and 100 metre, and an inner boundary produced 4 tonnes per second and metres in diameter. One effect of layer exists several mean free generally production rates were 2 this spallation of fragments is that paths above the nucleus. The x 1028 - 2 x 1029 s-1. 2001 A2 the nucleus remains extremely outer boundary is the transition to showed strong self absorption as cold. The structure appears to be free flow at 104 - 105 km. In it had a very strong emission line. BAA COMET SECTION NEWSLETTER 2000 October 9

18 In 2002 C1 H2 O was detected to investigate how the wind than a few Kelvin and there is lots and the 16O/18O ratio was around changes. 2001 A2 (LINEAR) of evidence for the two models. 500, similar to the cosmic ratio. showed a slender ion tail for most 1999 S4 showed metre sized Nicolas Biver and his colleagues of December and January, with no cometisimals and Kreutz had used several millimetre wave disconnection events, implying a sungrazers break up to metre to 10 telescopes to compare 25 comets. slow polar wind. 2002 C1 has metre sized objects. All the CH3CN was quite variable. The shown lots of disconnection Kreutz fragments and comets seen HNC/HCN ratio varied with solar events, which are a good match to so far would only sum to a body a distance. The variation in CH3OH current sheet crossings. There is few kilometres in size. 1993 F2 was far greater than in HCN (<1% an equatorial type of solar wind (D/Shoemaker-Levy) stretched at to 6%, around 2% in JFC). H2CO north of the heliospheric current perijove, fragmented and then re- was also variable, with a weak sheet (HCS) and polar south of it, accreted into the objects seen. correlation with CH3OH in LPC. though the polar wind was slower This concept explains lots of the Four CO rich comets were all than 750 km s-1. The location of features of the size distribution, HFC and CO was low in SPC. the HCS may vary from that with the biggest objects in the H2S was quite variable at 0.1% - expected from the photospheric centre and the re-entry where 1.5%. CS/HCN may also vary magnetic field measurements. there seems to be a greater surface with solar distance, being about 2002 Q4 (NEAT) will be a good area than can be explained by the 0.8 at 1 AU. Generally NH3 is probe of solar wind conditions. mass. The regolith may hide any around 0.5% of water. rubble structure. The maximum A glitch in proton numbers density is 1.65 for a tightly The FUSE spacecraft has measured by Ulysses was seen on packed agregate, though actual observed lots of UV emission 1996 May 1, with a coincident estimates (for example from non- lines, and around 50% remain change in the magnetic field. If gravitational forces) suggest a unidentified. There is no caused by an encounter with the value of 0.4. The breakup of evidence for argon in comets from tail of 1996 B2 (Hyakutake) this 1993 F2 suggests a value about 1 the observations, so it must be at implied a tail 3.8 AU long and and the same comes from IDPs least 10 times less than solar. with a 740 km s-1 wind speed the (Interplanetary Dust Particles). Comets can't therefore be the particles would have been emitted However meteorites show a source of argon in Venus' 8 days earlier. The tail is a long higher density than their parent atmosphere. FUSE has made the curved structure, about twice the bodies. The size distribution of first detection of neutral nitrogen diameter of the Sun at the nuclei varies as N(r) > r ~ r-1.6; in comets, but can't account for spacecraft distance. The smaller objects are probably the source. By looking at isotope orientation was not quite as under-represented and the original ratios and relative concentrations expected. There is a question of distribution may be steeper. they have showed that comet how it lasted so long, and possibly Perihelion distance has no effect 1999 T1 was never warmer than magnetic field draping protected on the derived slope parameter. 40 - 45 K and comets 2001 A2 it. Images taken on April 23 will 22P/Kopff has a rotational light and 2000 WM1 were never be important in understanding the curve of 12.3 hours and amplitude warmer than 60 K. observations. On March 1, the 0.5m, which implies an axial ratio Earth was inside the tail, which of more than 1.59. For 2P/Encke Some comets show no features in was curved, though less so than in it is 7.26 hours and 0.3m and the the coma. The features in those May. This could give a longer tail comet is probably smaller than 4 that do may be stationary or than predicted by geometrical km. For 6P/d'Arrest it is 7.2 varying, and if varying may be considerations, however the hours and 0.1m, giving a size of periodic or one off. Jets are feeling was that observers 1.5 km. Generally the measured consistent with active areas. reporting very long tail lengths sizes are 1.5 to 2.5 km for an Projection effects are very might have been confused by the assumed albedo of 4%. The important, eg a double jet feature geigenshine. nuclei of 28P and 124P when far may be explicable if we are from the Sun are redder than the looking directly at it. 1993 Y1 X-ray emissions from comets Sun. (McNaught-Russell) and 1996 Q1 were now thought to be caused by (Tabur) only showed gas jets - charge exchange of highly ionised Gonzalo Tancredi spoke about there were no dust jets. 1P/Halley atoms, eg O6+, in the solar wind ways of measuring the nucleus also showed some gas jets with no picking up electrons from the diameter. It can either be visited, dust. They seem fairly common, coma. A clear emission line was observed when very distant or the so gas and dust jets may be seen in 1999 S4 prior to its effect of the coma subtracted. For formed in different ways. breakup. C5+ and O7+ were seen the latter two techniques a plot of in 1999 T1 (McNaught-Hartley). the absolute magnitude against r The solar wind at solar minimum should either show a constant is very variable in equatorial Paul Weissman reported on value or reach a minimum. A regions, with speeds of 300 km s-1 cometary nuclei. We have phase coefficient and a geometric and disconnection events in comet imaged 1P/Halley and albedo of 4% is used to estimate ion tails are observed. At polar 19P/Borrelly, but at best the the effective radius. There are latitudes (>30°) the wind is fast resolution is 50 metres. There are good results for this technique and constant at around 750 km s-1. various models of a nucleus: with comets 1P and 19P, which At solar maximum it is variable Classical Whipple, Fractal have been visited. There is even in polar regions, with much Aggregate, Rubble Pile and Icy general agreement between less fast smooth wind conditions. Glue. The middle two are more ground based and HST John Brandt and others have used likely as there is no heat source measurements, except for amateur photographs and images that could head the nucleus more 147P/Kushida-Muramatsu, where BAA COMET SECTION NEWSLETTER 10 THE COMET'S TALE the HST value is clearly wrong. A replacement for a successful The survey of JFCs to q=2 is model must be able to predict, fit complete (ish) and suggests a the observations and be physically magnitude index of -3.4 (or a realistic. The classical non- cumulative index of -0.8). To gravitational model of Marsden measure more distant comets a was invented years ago to telescope larger than 3 metres is improve orbital fits and includes needed. Of around 230 JFCs, 100 radial and transverse forces linked have had their nuclear magnitude to g(r). This can be modified to determined, however there may include a normal component and a be biases. The distribution is delayed maximum. A newer nearly linear up to a nuclear model is the rotating jet model, magnitude of 17, but then flattens averaged over one rotation. For The absolute magnitude of 2P/Encke with a cut-off at 20. Very few 19P/Borrelly the classic model intrinsically faint comets with q < gives a poor fit to the The CLICC/A catalogue of comet 2 have been found recently. observations. The modified magnitude estimates has been Options are that break-up removes model does better, with a DT of extended for 21 LPCs observed the small ones, mantling occurs, 51 days before perihelion, when between 1959 and 1976. It can be or they loose all their volatiles. the reported rotation pole was in found at the solar direction. If the jet is at http://www.ta3.sk/~astrsven Hal Levison looked at fading in the rotation pole the new model comets. There is a big matches the observations. For Comet 53P was in a Jovian moon inconsistency between models of 2P/Encke the modified model like orbit some 600 - 1000 years delivery of OCCs into the inner does no better than the classical ago. It is not a Trojan, though it solar system and the observations, model, and whilst the jet model is currently close to a 'horse-shoe' so OCCs must disrupt. Two does better, it gives a different like orbit with respect to Jupiter. dormant external returning comets rotation pole to that derived by P/1997 V1 is in a 'horse-shoe' like have been observed, but there Sekanina. Sekanina's pole doesn't orbit and may have been a Trojan should have been 200! There is a match the light curve over the last in the past. In the future it will do similar ratio for extinct HFCs, twenty years, though the new pole 11 retrograde orbits about Jupiter. with 9 seen compared to a position does match his precessed P/1998 U4 may undergo prediction of 1100. JFCs however pole position. The model temporary capture in the future don't disrupt at this rate, with confirms Sekanina's two source for around 500 - 2000 years. some 20% being dormant; a regions, with 2° per apparition P/1999 WJ7 is at the end of a typical example is 2000 QN130. precession, with an obliquity pole period of 'horse-shoe' like orbit Dynamically new comets are of 35±15° and a rotation pole at and P/2000 Y3 is in a 'horse-shoe' often anomalously bright, 220° RA, 40° dec and the jet orbit. however there is still a problem positions remaining constant. with the flux being much higher The radial profile of SDO 29981 than observed. A full copy of this (1999 TD10) measured from talk is at images is flatter than stellar http://www.boulder.swri.edu/~hal/ images and it therefore shows talks.html. Modelling suggests evidence for a coma. that the majority of new OCCs reach q at 30 - 40 AU, with Asteroids roughly constant numbers reaching perihelion between 0 and There are several asteroid 30 AU. The JFCs must come missions planned. Dawn to Vesta from a flattened Kuiper belt. Jonathan Shanklin, Brian Marsden and and Ceres for orbital mapping and Another modelling paper looked Sebastian Hoenig at the ACM. Muses C, which will launch at the at the origin of JFC and HFCs end of this year, to 1998 SF36. from SDOs. There are a number I presented a paper on BAA Stardust is flying past Annefrank of differences between theory and comet observations and included on November 2 and will test observation. The SD model an updated version of the operations for 81P/Wild. produces more JFC than HFC as estimated absolute magnitude of observed, but a thick disk cannot 2P/Encke over the last 50 years, 2002 NT7 had an impact be the source for them. which shows no significant probability of 1:70,000 up to July 23. Now an impact in 2019 is not change. I also showed that -7 Carey Lisse et al looked at ageing periodic comets tend to have a possible, but one in 2060 is at 10 in comets. Short period comets larger log r coefficient than do though negative on the Palermo emit dust as large dark particles of non-periodic comets. There is a scale. Several speakers on impact high mass whilst LPCs emit small general trend for comets with a topics and orbital calculation were high albedo particles. They brighter absolute magnitude to rather too wrapped up in the suggest that SPCs become extinct have a larger log r coefficient, maths of their calculations, with by mantle formation over a period little attention to the real world. It 3 4 though this does not apply to of 10 - 10 years, disintegrate, or 'new' comets from the Oort cloud. would need 30 Arianne launches are ejected from the solar system There is no obvious correlation to deflect it from a 2060 or hit the Sun. 1999 S4 probably between absolute magnitude and encounter. The Italian didn't break-up as a result of perihelion distance. I've put a Spaceguard centre and JPL plan rotational splitting. version of the poster on the web, to create a database of each including all the figures. observing station so that a BAA COMET SECTION NEWSLETTER 2000 October 11 statistical distribution of errors gives rise to rubble piles. 216 period of 60 - 600 days. So far and biases can be applied to each Kleopatra is an M type asteroid in there is no information on density. astrometric observation. In order the shape of a 'dog bone' and may to reach the Spaceguard target (all be a residual metallic core frozen Formation of binaries could be by km sized NEOs within 10 years) into shape. tidal splitting (NEOs only), searches would have to be rotational fission, impact or complete to 21.5m now - they The shortest measured rotation disruptive capture. The large aren't! LINEAR would take until period of any asteroid is 76.8 separations of TNOs are not around 2035, though PanSTARRS seconds. Smaller objects rotate caused by tidal evolution and their could do it in six years. faster, but it is impossible to formation mechanism is Undiscovered NEOs are probably measure much faster periods with unknown. We would expect the intrinsically harder to discover sub 2-m class telescopes. It is secondaries of NEOs to be and all the search teams together possible to get fast rotators from rotationally locked, like the moon. will only get to 90% by 2014. the break up of a rubble pile. NEO binaries form by spin-up Possibly 50% of the most easily and mass shedding, most likely A solar concentrator gives quite accessible NEOs are fast rotators the result of disruption during an effective means of moving a and therefore not easy to land on! close planetary encounters. MBA small NEO over a five year or Most asteroids with regolith will binaries form from impact ejecta. longer period. Several NEOs have ponds and cracks, which fill The low density implies either a require a smaller DV to with fines if seismic shaking force high porosity or a high volatile rendezvous with, than do Mars or is comparable to gravity. They content. Venus, and one has a smaller show weak to moderate albedo value than for the moon. A hit features and even large bodies The rotational variant of the from a large object is likely every may show irregularities. Yarkovsky effect called YORP 400,000 years with a small one can explain some of these rapid every 1000 years. Objects on The binaries are important rotations. Asteroids can spin up imminent collision course with individually, as a population and and self destruct. These forces the Earth will be undetectable due because the NEO, MBA and are as important as gravity and to their lack of motion 3 - 4 weeks TNOs are different. NEO 2000 collisions in asteroid evolution. before impact. DP107 is a pair of 800 and 300 m The Yarkovsky effect on bodies diameter separated by 2.6 km. smaller than 20 km can transform Binary asteroids were a big theme Radar observations give very MBAs into NEOs. The YORP of the meeting and William good, rich data. The secondary is effect is important for spin, Merline gave an introductory talk. always brighter in radar images, obliquity and configuration of km There are 7 TNOs (Trans which can currently only view sized asteroids. There is evidence Neptunian Objects) with known NEOs. About 16% are binary, for the Yarkovsky effect working satellites, 8 MBAs (Main Belt with typical size ratios of 1:3, in the orbits of members of the Asteroids) and 14 NEOs, with a with the secondary orbiting at 5 Eos family and modelling further 8 binary NEOs detected times the primary radius, with a suggests an age of 2.1 Gy. from light curves. They have period of about a day. Densities Asteroid groups can be identified densities between 1 and 3 (times are between 1 and 2.6 implying from their proper elements and water). There are a variety of high porosity. Primaries are another recently identified group formation mechanisms. The TNO spherical and fast rotators. MBA is the Karin group, which from its satellites must have formed in can be detected with adaptive compact grouping must be young. situ, but the NEOs by optics on large telescopes. There Integrating the orbits back in time fragmentation. The TNOs are are observational selection effects gives a breakup age of 5.8 My, mostly cubewanos, and are too and satellites that are faint or at with the original body 25 km wide to have formed by small separations won't be seen. across. This means that members collisional breakup. Sizes range A few percent of MBAs are of the group should show fresh from 1:1 to 1:20. A small binary, with typical size ratios of surfaces, perhaps with water ice, secondary is likely to arise from 1:10, with the secondary orbiting and they may be the source of ejecta form an oblong object. at 10 times the primary radius, some zodiacal dust bands. A Rotational fission will give rise to with a period of about four days. satellite visit to members of the close equal components. Tidal Densities are between 1.2 and 2.3, group could help measure the disruption is likely to be common even for M type asteroids, which Yarkovsky effect, satellite in NEOs. He showed an is an implausible porosity for formation and crater counts impressive animation showing the them to be the source of iron (though these are probably effects of adaptive optics. Dactyl meteorites. There are a few large dominated by debris). The spin was the first positive detection in contact binaries, eg Nysa, Daphne vectors for Koronis family 1993, with Eugenia/Petit Prince in and Hector. TNO binaries can be members are bi-modal. 1998. Some light curves give seen with HST or medium sized convincing evidence of duplicity. ground based telescopes. No new Al Harris (JPL) asked 'How many Dactyl probably formed from a binaries were seen in a sample of Tunguskas are there?'. One way cratering event on Ida as its 200, however two and an already of estimating how many NEOs surface is only around 30 My old. known one, were found in a set of there are is to look at the re- Arecibo has 7.5 metre range 75 imaged with WFPC. About detection rates by search resolution and gives clear views one percent of TNOs are binary programmes of already known of NEO binaries. All NEO (or possibly 4%), with typical size bodies. To estimate the size of binaries are fast rotators and about ratios of 1:1 to 1:3, with the craters we can look at lunar 17% of NEOs are binary, secondary orbiting at 10 - 100 impacts, where the size of suggesting that tidal disruption times the primary radius, with a crater/size of body ratio increases BAA COMET SECTION NEWSLETTER 12 THE COMET'S TALE for smaller bodies up to 1:50. zodiacal dust bands may be in his talk. Ondrejov data shows Discovery statistics need to be associated with asteroid families multiple peaks in Orionid corrected for 'missing' detections or perhaps a recent break-up. observations, with significant near the limit of the system, and at Perhaps as many as 85% of IDPs shifts from one year to the next. faint magnitudes the efficiency come from one source, possibly Both Orionids and eta Aquarids may be 10-5. Up to a limit of Veritas, a C-type asteroid, which extend over 14 days and the link H=18 (roughly equivalent to a broke up around 50 My ago. Dust with comet Halley is established kilometre) there are around 1100 must have been more significant beyond doubt. The eta Aquarids objects. For smaller objects the away from the present epoch, last from L 37 - 51°, with statistics are poor. To make an possibly giving a climate signal. enhanced activity between 42.5 estimate he took 1000 known The near 100 Ky periodicity in the and 47°, whilst the Orionids last NEOs, ran the elements for 100 Quaternary climate might be from 202 - 216° with a double years and found 5000+ passages related to chaotic transport of maximum between 208 and 210°. at less than 0.3 AU. He then NEOs through variation in the The mass index is 2.2 and 1.8 convolved this with the LINEAR orbital eccentricity of Mars. respectively. coverage, though note that LINEAR can't detect objects The Klet observatory has a new, Double station recording from moving at more than 12° per day specially designed 1m f3 Ondrejov suggests that brighter (which is why they often don't see telescope, with 1024 pixel CCD Orionid and perhaps Perseid close approachers until after they camera and a 33' field for the meteors start higher in the pass). This gave an estimate of KLENOT project, which is atmosphere (120 Km). Slow 106 Tunguska sized objects or 1 designed to provide astrometry of meteors penetrate more deeply (to per 1000 years. A questioner NEOs, comets, Centaurs, TNOs 80 Km). They do not see however noted that acoustic etc and in particular to make cometary (ie fragile) meteoroids monitoring suggests an object this follow up observations. They on orbits with small perihelion size every 120 years. have provided confirmation for 48 distances. Generally light curves NEOs, including a 21.9m Amor from the Perseids, Orionids and Boris Ivanov and Jay Melosh had object, 5 comets and the 'B' Leonids are symmetric with peak numerically modelled asteroid component of 57P. They have brightness near the middle. Pavel impacts and concluded that they discovered an Apollo 2002 LK. It Koten has written meteor video do not induce volcanism. Oceanic can be worth measuring the processing software - the present crust is young, less than 250 My, position of around three numbered version is for DOS, but a and there are no major (> 300 km) minor planets during the course of Windows version is being crater remnants. Hot spots are astrometric work as this can help developed. small, and unlikely to be hit. trace errors of measurement or Flood basalts link to tectonic systematic effects. Station 940 A Russian speaker suggested the activity. A large impact can shows residuals of around 1" in existence of meteor micro- create a hot spot, but this is RA and dec over the last few showers with activity of perhaps created by shock heating and is years, with 951 having 0.6" and 1/10 that of major showers. He not intrinsic to the Earth itself. 0.4" respectively. suggested that they might arise by Melting is 1 - 3 orders of gravitational separation from the magnitude less than associated There are no KBOs with low major showers. Unfortunately he with large igneous provinces. It eccentricity orbits beyond 50 AU. didn't see some of the major would be unlucky to hit a young Deep searches should have found showers and I suspect that there hot spot and therefore this is not a them, unless they are located in a may be noise in his data. regular geological process. There thin disk in the invariable plane of are varying estimates of the ratio the solar system. Alternatively The North Taurids are active from of long period comets to asteroid they could have been cleared by a October 16 - November 29, whilst impacts ranging from 5 to 30%. recent stellar passage or a Mars the South Taurids are active from We have some idea of the LPC like planetoid at 60 AU. There October 4 to November 24. flux now, but how can we tell the are many biases in the follow up Meteors generally associated with difference in impact structures? of TNOs, for example if the the Taurid complex are active David Wallis suggested by object is assumed to be a plutino from September 16 to December possibly using the difference in it is most likely to be recovered if 29 (N) and September 25 to azimuth of impact direction as the it is one. To do good statistics it December 19 (S). It is important orbital distribution in the two is necessary to use a well to take account of radiant motion groups is different. Measuring the characterised survey and this as it moves through over 90° in crater bowl shape asymmetry shows that some 20 - 25% are RA. 1993 KA2, 1998 VD31, gives the impact direction and SDOs and <3% plutinos, with a 1999 VK12 and 2002 MX are crater rays may confirm this for new class of Extended SDOs. probably associated with the some lunar and Martian craters. Richard Donnison suggests that complex, but 2201 Oljato is There has been no practical study there should be a predominance of probably not. Taurids generally so far, and questioners were large bodies in the TNO have a higher critical mass than sceptical if the technique would distribution. the Orionids (5 mg cf 0.8 mg). work. Ziolkowski suggests that Meteors 2P/Encke and 1966 T1 (Rudnicki) IDPs are quite different to are both member of the Taurid meteorites : they are small grains There are over 100 years of complex. If so, integrating back with a high carbon content and observations of meteors from the orbit of 2P until the longitude probably originate in a few comet 1P/Halley. Sadly Anton of perihelion agrees with that of discrete sources. The three main Hajduk didn't use any BAA data 1966 T1 should give the time of BAA COMET SECTION NEWSLETTER 2000 October 13 separation. This gives 4.35 x 104 explained by ejection from the subject to significant hearing and years, comparable to the period of comet as the ejection velocity this suggest there may be highly 1966 T1, which is about 4.5 x 104 would have to be around 0.003 processed material in the Oort years. mm/sec, much less than the cloud. expected 30 cm/sec. It probably There are two more Leonid occurred after the last perihelion Comets with aphelia less than 7 storms expected in 2002 on of the debris, about 6 days before AU produce the bulk (90%) of November 19 at 03:58 - 04:15 and encountering the Earth. Peter meteoric material. HFC produce 10:36 - 11:15. The second peak is Jenniskens suggests that there 5% and long period comets (P > from the 1866 trail and may have could be a further significant 200 y) 5%. The model predicts a peak ZHR of 2850, with a 2 Leonid shower in 2006. The the observed helion/anthelion hour duration. There is a visibility of 'periodic' outbursts is distribution of sporadic meteors. Lorentzian distribution of governed by Jupiter pulling particles long each debris trail, around the solar system Conclusion and the trail is displaced from barycentre. year to year. Bright Leonids (~-2) Richard Binzel summarised the tend to be brightest at the end of A fireball recorded by the meeting for the final talk. He their flight, and these probably European Fireball Network on thought that inter-relationships have greater strength and are 2002 April 6 lead to the recovery between the various bodies were larger. The final flare of a fireball of a 1.7 Kg meteorite by amateur amongst the most important may be richer in CaAl. 0m astronomers in July and this was aspects. We are getting some meteors tend to have a variety of exhibited at the meeting. It was geophysics of asteroids, for light curves. There is no evidence found a little to the east of the example on Eros. Fundamental for ageing in Leonid meteors from predicted fall ellipse. The orbit is questions about comets remain. different trails, though there are clearly related to that of Pibram They have an aggregate structure. significant differences. A and implies the existence of a We are getting better nuclear network of video cameras in meteroid stream. Another fireball magnitude distributions. 2/3 of Japan recorded the 2001 shower. on 2001 November 17 was so OCC formed beyond 30 AU with Significant variations in the rates bright (-18m) that it was detected rest forming between 5 and 30 from north to south reflect the by a radiometer at night. AU. The Oort Cloud is the source structure of the trail. The of long and short period comets, population index was higher at 2.2 The Arecebo radar shows a clear with the Kuiper belt for JFC. after the 1815 (4 revolution) peak peak in fast meteors between 04 TNOs are a growing field and we compared to 1.9 before the 9 and 08 LAT. An unusual fireball have discovered the same number revolution peak. The Japanese was photographed from Ondrejov, as there were MBA in 1900. also set up a network of school which showed an apparently There are dynamically "hot" observers. The results are 'strong' meteor in a retrograde objects, which are blue/grey in scattered but the mean of 171 orbit, with q 1.01, Q 6.0 and colour, and "cool" objects (ie in groups (1800 students) agrees lacking in sodium. Sodium stable orbits) that are red. well with the IMO results. lacking meteors occur in two Satellites are very important. Australian image intensifier groups: those in sun approaching Probably one size does not fit all. results from 2001 shows peaks at (q < 0.25) prograde orbits with Highlights for meteors included 18:02±3 (9 revolution, 1699) and low to moderate inclinations and the Leonids, recovery of the 18:17±3 (4 revolution, 1866) but an inner halo with q ~ 1 and in Neuschwanstein meteorite (only no evidence for an 18:30 peak high inclination, often retrograde the 3rd European recovery) and the reported by visual observers. orbits. They could be related to link of IDPs to showers. The Short lived enhancements of the exinct HFC as proposed by Yarkovsky effect is important for Leonid rates ( > 15 within a few Levison, however the non- meteorite delivery. seconds) in a linear distribution chondritic structure argues against (cf Shoemaker-Levy 9) cannot be this. Inner halo meteoids are Review of comet observations for 2002 April - 2002 September

The information in this report is a comets, though this is not the IAU when at its brightest (11m) at the synopsis of material gleaned from convention. end of the year. IAU circulars 7881 – 7979 and The Astronomer (2002 April– 7P/Pons-Winnecke Although few 29P/Schwassmann-Wachmann 2002 September). Note that the confirmed observations were This annual comet has frequent figures quoted here are rounded received, reports circulating on outbursts and over the past few off from their original published the internet suggested that the years seems to be more often accuracy. Lightcurves for the comet entered visual range in active than not, though it rarely brighter comets are from April. It was several magnitudes gets brighter than 12m. This observations submitted to The fainter than expected and the comet is an ideal target for those Astronomer and the Director. A majority of observations were equipped with CCDs and it should full report of the comets seen made from the Southern be observed at every opportunity. during the year will be published Hemisphere. It spends 2002 in Capricornus and in the Journal in due course. I was at opposition in early August, have used the convention of 22P/Kopff Although it continues fairly close to Neptune. designating interesting asteroids to brighten, the solar elongation Unfortunately opportunities for by A/Designation (Discoverer) to decreases and it is poorly placed UK observers are limited, as its clearly differentiate them from altitude will not exceed 20° from

BAA COMET SECTION NEWSLETTER 14 THE COMET'S TALE this country. The comet has MPEC 2002-N14), but a check Ehime, Japan, 0.60-m reflector + undergone a series of outbursts with Pravdo on July 12 did not CCD); 9.68, 15.4 (Nakamura); over the summer. reveal anything obvious at the 18.70, 15.7 (K. Kadota, Ageo, July 1 expected position of the Saitama, Japan, 0.18-m reflector + This comet appears again to be in new object. Following a request CCD); July 5.27, 13.4 (A. Hale, outburst, as indicated by the by the Minor Planet Center, M. Cloudcroft, NM, 0.41-m following total-magnitude Tichy and J. Ticha (Klet, reflector); 10.24, 13.3 (Hale); estimates (visual unless otherwise KLENOT 1.06-m reflector) 10.95, 14.1 (K. Sarneczky, noted): Mar. 20.83 UT, [16: (T. located the new object, describing Agasvar, Hungary, 0.38-m Kojima, Chiyoda, Japan, 0.25-m it as diffuse and having a coma of reflector); 11.59, 14.5 (Y. Ezaki , reflector + CCD); 27.80, 14.4 diameter 8"-10"; as did G. Masi Toyonaka, Osaka, Japan, 0.30-m (Kojima); May 8.46, 13.5 (A. and F. Mallia (Campo Catino, 0.8- reflector + CCD). [IAUC 7937, Hale, Cloudcroft, NM, 0.41-m m f/8 reflector), whose coaddition 2002 July 24] reflector); 9.46, 13.3 (Hale); of five images (for a total 21.45, 13.3 (Hale); June 8.39, integration of 20 min) showed a Z. Sekanina, Jet Propulsion 12.3 (Hale; near-stellar well-defined 12" coma and a Laboratory, writes: "Very appearance); 9.75, 12.0 (A. delicate northeast-southwest preliminary analysis of the Nakamura, Kuma, Ehime, Japan, elongation. The object was again relative astrometry of the two 0.60-m reflector + CCD; strong included in the July 13 NEAT brightest nuclei (cf. MPEC 2002- condensation). [IAUC 7918, 2002 NEO-candidate report but with no O10) has been completed, June 13] remark about its appearance. employing a new computer code recently developed by P. W. 46P/Wirtanen is a morning The positions are fully consistent Chodas and myself. The object in 2002, fading from its with the orbital elements for parameters of the standard model best magnitude of 11. The solar comet 57P on MPC 45964 for split comets are now elongation only increases from (ephemeris on MPC 44939) with determined with full account of around 45° to 60° by the end of T for this "component B" delayed the planetary perturbations and the year, so it is never very well by 0.19 day (i.e., to 2002 July the nongravitational effects on the placed. The first visual 31.37 TT). It should be noted that principal nucleus. The results observation was reported in early comet 57P was anomalously suggest that nucleus B could have August when the comet was bright at its unfavourable 1996 broken off from primary A near around mag 11.5. Observations return (T = 1996 Mar. 5.7; m1 = perihelion in 1996. If the event reported around the equinox 13.3 at the first postperihelic had occurred exactly at suggest that the comet has observation on July 24.8--see perihelion, plausible values for experienced an outburst and has MPC 27482--some 5 mag brighter the nongravitational deceleration brightened to magnitude 9. The than expected). [IAUC 7934, (4-8x10^-5 solar attraction, as B comet is in Virgo in November 2002 July 13] is obviously a persistent and December. companion; cf. Sekanina 1982, Y. R. Fernandez, D. C. Jewitt, and Comets, ed. L. L. Wilkening, pp. Observations received prior to the S. S. Sheppard, University of 251-287) require that B separated outburst (7) give a preliminary Hawaii, report the detection of an from A with a reasonably low light curve of 8.5 + 5 log d + [15] additional 18 components (C-T) velocity, whose transverse log r which is quite similar to that of comet 57P (cf. IAUC 7934) in component ranged from 0.5 to 1 of 1997. observations taken on July 17.5 m/s in the direction opposite the and 18.4 UT with the University orbital motion and whose normal 57P/du Toit-Neujmin-Delporte of Hawaii 2.2-m reflector. R-band component was some 0.4-0.5 m/s is currently too faint for visual magnitudes range from 20.0 to toward the north orbital pole. observation. It was observed in 23.5. The components range from These solutions are independent outburst at the 1996 return and in well condensed to diffuse with of the radial component of the July 2002, as it approached little central condensation and separation velocity. Similar perihelion, NEAT discovered a have comae of diameter 1"-5". solutions are also found for secondary component. A further Components I, K, L, N, P, and T separation times 100 days before 18 components were discovered show a lack of central and after perihelion, except that by Fernandez et al at the condensation. The components the deceleration then correlates University of Hawaii. are delayed with respect to T = with both the transverse and radial 2002 July 31.181 TT for components. Because of the A faint object reported as a component A by the following comet's extremely low orbital possible NEO candidate on July times (in days): C, +0.012; D, inclination, it is doubtful that the 12.21 by S. Pravdo, Jet Propulsion +0.037; E, +0.053; F, +0.078; G, separation parameters can ever be Laboratory, on behalf of NEAT +0.156; H, +0.164; I, +0.170; J, determined with high accuracy. and described as appearing +0.180; (B, +0.188); K, +0.194; All examined solutions yield cometary was recognized at the L, +0.194; M, +0.224; N, +0.226; essentially the same ephemeris, Minor Planet Center as being on O, +0.240; P, +0.271; Q, +0.309; which shows that the projected the line of variation and to have R, +0.311; S, +0.313; and T, separation of B from A will the motion of comet 57P, but to +0.354. [IAUC 7935, 2002 July diminish in the coming weeks. be displaced from that brighter 20] The offsets and position angles comet (which was not included in are as follows (0h UT): 2002 Aug. the dataset) by more than 0.2 deg Total magnitude estimates for the 4, 853", 259.1 deg; 14, 814", on the 1.2-m Palomar Schmidt primary component (visual unless 259.1; 24, 758", 259.0; Sept. 3, frames. NEAT had reported the otherwise noted): June 5.71 UT, 694", 258.7; 13, 631", 258.3; 23, brighter comet on July 1 (see 15.6: (A. Nakamura, Kuma, 571", 257.7; Oct. 3, 516", 257.0. BAA COMET SECTION NEWSLETTER 2000 October 15

It is unlikely that companions C-T 2002 Q12 SOHO (IAUC 7969, 2002 September 13) (cf. IAUC 7935) are all products Kracht Group comets 2002 Q13 SOHO (IAUC 7969, 2002 September 13) of the same event. In particular, 2001 Q8 SOHO (IAUC 7952, 2002 August 10) 2002 Q14 SOHO (IAUC 7969, 2002 September 13) C-F were probably released from 2001 R8 SOHO (IAUC 7952, 2002 August 10) 2002 R6 SOHO (IAUC 79xx, 2002 September ) A more recently than B was. 2001 R9 SOHO (IAUC 7952, 2002 August 10) 2002 R7 SOHO (IAUC 79xx, 2002 September ) Some of nuclei M-T may be 2001 N2 SOHO (IAUC 7956, 2002 August 19) 2002 S2 SOHO (IAUC 79xx, 2002 September ) fragments of B, but a more 2002 Q8 SOHO (IAUC 7963, 2002 August 31) 2002 S3 SOHO (IAUC 79xx, 2002 September ) complex fragmentation hierarchy 2002 Q10 SOHO (IAUC 7969, 2002 September 13) were discovered with the SOHO is also possible. Accurate were discovered with the SOHO LASCO coronagraphs and have astrometry on existing images and LASCO coronagraphs and have not been observed elsewhere. additional observations may allow not been observed elsewhere. They were were not expected to one to make more, but not very, survive perihelion. definite statements in the future.'' Kreutz group comets [IAUC 7946, 2002 August 3] 1998 V9 SOHO (IAUC 7916, 2002 June 7) One of the brighter objects was 1998 X12 SOHO (IAUC 7916, 2002 June 7) 2002 J3, discovered by 65P/Gunn was discovered in 1999 W2 SOHO (IAUC 7898, 2002 May 13) Kazimieras Cernis on May 13. I 1970 after a perturbation by 2000 C7 SOHO (IAUC 7919, 2002 June 14) independently discovered it at Jupiter in 1965 had reduced the 2000 F2 SOHO (IAUC 7913, 2002 May 30) 08:30 on May 14, however this perihelion distance from 3.39 to 2000 F3 SOHO (IAUC 7913, 2002 May 30) was 18 hours after the discovery 2.44 AU. In 1980 two 2000 H6 SOHO (IAUC 7899, 2002 May 13) had been posted and by then the prediscovery images were found 2000 H7 SOHO (IAUC 7899, 2002 May 13) comet was very obvious. I should on Palomar plates taken in 1954. 2000 T5 SOHO (IAUC 7919, 2002 June 14) have spotted it the previous day as The comet can be followed all 2000 T6 SOHO (IAUC 7919, 2002 June 14) I had looked at the C3 images on round the orbit as it has a 2001 H8 SOHO (IAUC 7918, 2002 June 13) Monday evening. relatively low eccentricity of 0.32. 2001 J5 SOHO (IAUC 7931, 2002 July 2) It returns to perihelion in May 2001 K10 SOHO (IAUC 7931, 2002 July 2) Marsden Group comets next year. 2001 L11 SOHO (IAUC 7952, 2002 August 10) 2002 R1 SOHO (IAUC 7969, 2002 September 13) 2002 G4 SOHO (IAUC 7882, 2002 April 22) 2002 R4 SOHO (IAUC 79xx, 2002 September ) The visual and CCD observations 2002 G5 SOHO (IAUC 7882, 2002 April 22) were discovered with the SOHO received so far (13) give an 2002 H1 SOHO (IAUC 7882, 2002 April 22) LASCO coronagraphs and have uncorrected preliminary light 2002 H3 SOHO (IAUC 7886, 2002 April 29) not been observed elsewhere. curve for the 2002 apparition of 2002 H4 SOHO (IAUC 7886, 2002 April 29) 4.8 + 5 log d + [15] log r 2002 H5 SOHO (IAUC 7886, 2002 April 29) Meyer Group comets 2002 H6 SOHO (IAUC 7886, 2002 April 29) 1997 O2 SOHO (IAUC 7931, 2002 July 2) 67P/Churyumov-Gerasimenko 2002 H7 SOHO (IAUC 7948, 2002 August 3) 1997 U8 SOHO (IAUC 7931, 2002 July 2) is a morning object in 2002. 2002 J1 SOHO (IAUC 7897, 2002 May 9) 1997 U9 SOHO (IAUC 7931, 2002 July 2) Again the elongation is not good, 2002 J2 SOHO (IAUC 7897, 2002 May 9) 1998 V8 SOHO (IAUC 7916, 2002 June 7) increasing from around 50° to 2002 J3 SOHO (IAUC 7899, 2002 May 13) 1998 W7 SOHO (IAUC 7916, 2002 June 7) 100° at the end of the year. The 2002 J6 SOHO (IAUC 7909, 2002 May 28) 1999 F3 SOHO (IAUC 7898, 2002 May 13) comet's track closely parallels that 2002 J7 SOHO (IAUC 7909, 2002 May 28) 1999 K16 SOHO (IAUC 7842, 2002 March 5) of 46P/Wirtanen ending the year 2002 J8 SOHO (IAUC 7913, 2002 May 30) 1999 L9 SOHO (IAUC 7842, 2002 March 5) on the border of Leo and Virgo. 2002 K3 SOHO (IAUC 7909, 2002 May 28) 2000 J8 SOHO (IAUC 7899, 2002 May 13) A few observations reported on 2002 K5 SOHO (IAUC 7913, 2002 May 30) 2000 N4 SOHO (IAUC 7899, 2002 May 13) the internet suggest that it was 2002 K6 SOHO (IAUC 7913, 2002 May 30) 2000 X9 SOHO (IAUC 7919, 2002 June 14) th around 13 magnitude in 2002 K7 SOHO (IAUC 7913, 2002 May 30) 2001 C7 SOHO (IAUC 7936, 2002 July 22) September. 2002 K8 SOHO (IAUC 7951, 2002 August 10) 2001 K11 SOHO (IAUC 7952, 2002 August 10) 2002 K9 SOHO (IAUC 7951, 2002 August 10) 2001 L10 SOHO (IAUC 7952, 2002 August 10) 92P/Sanguin This comet was 2002 K10 SOHO (IAUC 7951, 2002 August 10) 2001 R7 SOHO (IAUC 7952, 2002 August 10) discovered in 1977, when it 2002 L1 SOHO (IAUC 7916, 2002 June 7) 2001 V6 SOHO (IAUC 7952, 2002 August 10) reached mag 13.5. The period is 2002 L2 SOHO (IAUC 7916, 2002 June 7) 2001 X10 SOHO (IAUC 7952, 2002 August 10) 12.4 years, which makes alternate 2002 L3 SOHO (IAUC 7918, 2002 June 13) 2002 A4 SOHO (IAUC 7875, 2002 April 12 returns unfavourable and in 1989 2002 L4 SOHO (IAUC 7918, 2002 June 13) 2002 H8 SOHO (IAUC 7951, 2002 August 10) it only reached 18th mag in large 2002 L5 SOHO (IAUC 7919, 2002 June 14) 2002 P3 SOHO (IAUC 7956, 2002 August 19) aperture telescopes. Magnitude 2002 L6 SOHO (IAUC 7922, 2002 June 17) 2002 R8 SOHO (IAUC 79xx, 2002 September ) predictions for the present return, 2002 L7 SOHO (IAUC 7930, 2002 July 2) were discovered with the SOHO which is similar to the discovery 2002 L8 SOHO (IAUC 7930, 2002 July 2) LASCO coronagraphs and have return, were based on the 1989 2002 M1 SOHO (IAUC 7930, 2002 July 2) not been observed elsewhere. return and made no allowance for 2002 M2 SOHO (IAUC 7930, 2002 July 2) 2002 P3 was SOHO 500. the method of magnitude 2002 M3 SOHO (IAUC 7935, 2002 July 20) estimation. To the surprise of 2002 M4 SOHO (IAUC 7935, 2002 July 20) Other SOHO comets some, the comet was an easy 2002 M5 SOHO (IAUC 7935, 2002 July 20) 1997 S4 SOHO (IAUC 7931, 2002 July 2) th object of 13 magnitude in early 2002 M6 SOHO (IAUC 7935, 2002 July 20) 2001 D1 SOHO (IAUC 7936, 2002 July 22) September. This is actually more 2002 M7 SOHO (IAUC 7935, 2002 July 20) 2002 Q6 SOHO (IAUC 7963, 2002 August 31) or less exactly the brightness 2002 M8 SOHO (IAUC 7948, 2002 August 3) 2002 Q9 SOHO (IAUC 7969, 2002 September 13) expected on the basis of the 2002 N1 SOHO (IAUC 7936, 2002 July 22) 2002 R5 SOHO (IAUC 79xx, 2002 September ) discovery return. 2002 O1 SOHO (IAUC 7936, 2002 July 22) were discovered with the SOHO 2002 O2 SOHO (IAUC 7936, 2002 July 22) LASCO coronagraphs and have I observed it with the 2002 O3 SOHO (IAUC 7936, 2002 July 22) not been observed elsewhere. Northumberland refractor on 2002 P2 SOHO (IAUC 7956, 2002 August 19) C/2002 R5, discovered in C2 September 1.88, estimating it at 2002 Q7 SOHO (IAUC 7963, 2002 August 31 ) imagery on September 5 by Rob 13.3. 2002 Q11 SOHO (IAUC 7969, 2002 September 13) Matson, appears to be related to BAA COMET SECTION NEWSLETTER 16 THE COMET'S TALE

C/1999 R1, a point first made by from 13th magnitude. The scatter R. Kracht. [MPEC 2002-S35, in observations is largely due to 2002 September 22] differences between visual and CCD methods. 2000 S5 (SOHO) was an unusual SOHO discovery, found in 88 observations received give an SWAN imagery. Although uncorrected preliminary light having a perihelion distance of curve of m = 9.0 + 5 log d + 2.1 0.60 AU, it remained outside the log r. LASCO field of view and was too far south and/or in the twilight for 2000 WM1 (LINEAR) became Northern Hemisphere comet visible to UK observers again in hunters. Nevertheless it might be April, but it quickly become large dectable on images taken in and diffuse and few observations November or December 2000. were reported. [MPEC 2002-H41, 2002 April 24] 2001 Q4 (NEAT) The comet was T. Makinen, Finnish discovered when still over 10 AU Meteorological Institute, Helsinki, from the Sun. The latest elements reports the discovery of another give T as 2004 May 15.9 with q at apparent comet (cf. IAUC 7327) 0.96 AU. Brian Marsden notes on from the second systematic survey MPEC 2002-R45 that the of hydrogen Lyman-alpha "original" and "future" barycentric emission appearing on SWAN values of 1/a are +0.000022 and - images (wavelength range 10-180 0.000723 (+/- 0.000022) AU**-1, nm) taken from the SOHO respectively. [2002 September 11] spacecraft during September- The "original value of 1/a November 2000 (discovery suggests that this is a new visitor observation below). Makinen from the Oort cloud. notes that all comets brighter than total visual mag approximately 11 The comet should be a bright can be seen on the SWAN full- object in May 2004. Adopting a sky maps. The stated uncertainty 859 visual observations received conservative magnitude law (7.5 in the reported positions is 0.5 give an preliminary light curve of log r), suggests a peak of around degree due to the resolution of the m = 6.7 + 5 log d + 9.6 log r 3rd magnitude, whereas the SWAN instrument. which does not take into account standard 10 log r gives around 0 the outburst. magnitude. Further positional and orbital information, together with an 2001 HT50 (LINEAR-NEAT) 2001 RX14 (LINEAR) Brian ephemeris to encourage searches The comet could reach 11th mag Marsden notes on MPEC 2002- of archival optical images, are or brighter at its two oppositions R45 that the "original" and given on MPEC 2002-H41. in 2003. 5 observations give a "future" barycentric values of 1/a Derived total visual magnitudes preliminary light curve of 1.7 + 5 are +0.000778 and +0.000259 (+/- from the Lyman-alpha fluxes log d + [10] log r 0.000003) AU**-1, respectively. (using a formula by Jorda et al. [2002 September 11] The 1992, Asteroids, Comets, Meteors 2001 K5 (LINEAR) The comet is "original value of 1/a suggests 1991, 285): 2000 Sept. 21.77 UT, distant and will remain at around that this is not a new visitor from 10.8; Oct. 1.42, 10.0; 5.23, 9.4; 14th mag visually for some time. the Oort cloud. 7.35, 8.4; 10.38, 7.7; 12.45, 7.3; 23 observations give a 14.37, 7.5; 17.40, 7.8; 21.38, 7.9; preliminary light curve of 1.9 + 5 The comet reaches perihelion at Nov. 4.42, 8.2. [IAUC 7885, 2002 log d + 9.0 log r 2.06 AU in January 2003 and April 25] could reach 10th mag. Visual 2001 OG108 (LONEOS). On observers were reporting it at March 28.84 I was able to see it in around 13th magnitude in early the Thorrowgood refractor, September 2002. despite strong moonlight and observing through trees, 2002 BV (P/Yeung) = 2001 estimating it at 10.2. The comet CB_40 An asteroid reported to became quite a diffuse object the MPC by William Kwong making it difficult to locate. Yeung of Benson, Arizona who was taking CCD images from 82 visual observations give a near Apache Peak with a 0.45-m preliminary uncorrected light reflector on January 21.49 was curve of 9.3 + 5 log d + 17.2 log r. linked to asteroidal observations Moonlight and the rapid rate of by Spacewatch and LINEAR, brightening would probably have including 2001 CB40. This prevented visual observation showed it to have a cometary orbit before early February. and Timothy Spahr was able to take images with the 1.2-m 2000 SV74 (LINEAR) This telescope on Mt Hopkins which distant comet will slowly fade showed it to be a comet. [IAUC BAA COMET SECTION NEWSLETTER 2000 October 17

7896, 2002 May 9] The comet GHz was detected with a peak J. E. Lyke, M. S. Kelley, D. C. has a period of 6.6 years and was integrated line intensity of 21.6 K Jackson, R. D. Gehrz, and C. E. at perihelion at 2.24 AU in mid km s**-1 on Apr. 26.8 inside the Woodward, University of March. It will fade from 17th 2' Odin beam. This corresponds to Minnesota (UM), report 1- to 12- magnitude. It is a Jupiter family a preliminary water-production micron photometry of this comet comet. rate of 1.7 x 10**29 molecules/s, on May 22.37 UT at the Mt. taking into account opacity Lemmon Observing Facility 1.52- 2002 C1 (Ikeya-Zhang) effects. The 110-101 line at m telescope (+ UM bolometer + H. E. Matthews, National 547.676 GHz of the (^18)O IRTF narrowband 'silicate' filters). Research Council, Victoria, isotopic variety of water was also No evidence for strong silicate British Columbia, and Joint detected. The average of Apr. emission was observed at 11 Astronomy Centre, Hawaii (JAC); 23.7-28.1 observations yields an microns; short-wavelength data and T. B. Lowe, JAC, report integrated line intensity of 0.24 were fit to a 5800-K reflected pointed spectral-line observations +/- 0.02 K km s**-1. Within solar blackbody, while the of comet C/2002 C1 made at the model uncertainties, the inferred observed spectral energy James Clerk Maxwell Telescope, H_2^(18)O production rate is distribution at longer wavelengths Mauna Kea, in the 1.3-mm and consistent with the terrestrial yields a blackbody color 0.8-mm bands: "The beamwidths ^(16)O/^(18)O ratio." [IAUC temperature of 270 +/- 15 K. to halfpower are about 21" and 7910, 2002 May 28] Observed magnitudes: [J] = 10.87 13", respectively. We have +/- 0.02, [H] = 10.42 +/- 0.01, [K] detected the groundstate rotational = 10.26 +/- 0.01, [L'] = 8.78 +/- transitions HCN 4-3 and 3-2, 0.28, [M] = 6.49 +/- 0.29, [N] = HNC 4-3 and 3-2 and CS 5-4. 1.98 +/- 0.24, [8.81 microns] = Observed integrated intensities (in 2.81 +/- 0.34, [10.27 microns] = mainbeam brightness K km/s) 1.33 +/- 0.06, [11.70 microns] = were: 3.65 and 0.71 (HCN 3-2, 1.18 +/- 0.31, and [12.49 microns] HNC 4-3, Mar. 23.95 UT), 4.10 = 0.34 +/- 0.31. [IAUC 7921, (HCN 3-2, Mar. 28.82), 0.71 2002 June 17] (HNC 3-2, Mar. 29.85), 18.4 (HCN 4-3, Mar. 30.98) and 4.47, An image by Martin Mobberley on May 4 0.62 and 0.74 (HCN 3-2, HNC 3- 2, CS 5-4, Apr. 7.93). CO has not G. Cremonese, Istituto Nazionale been detected in two attempts di Astrofisica (INAF) and (CO 3-2, Mar. 23.95 and CO 2-1, Osservatorio Astronomico, Apr. 7.93), the absolute upper Padova; A. Boattini, M. T. Capria, limit to the peak signal being 0.1 M. C. De Sanctis, and G. K. The velocity width (km/s) to D'Abramo, Istituto di Astrofisica halfpower measured using the Spaziale e Fisica Cosmica, CNR, HCN lines was 2.6 (Mar. 23.93), Rome; and A. Buzzoni, INAF and 2.4 (Mar. 28.82), 2.2 (Mar. 30.98) Telescopio Nazionale Galileo and 2.2 (Apr. 7.87) and thus (TNG), report observing the An image taken by David Strange on May appears to show a decrease with sodium distribution in the coma of 1 showing jet structure in the coma. increasing r." [IAUC 7876, 2002 comet C/2002 C1 on Apr. 20.17 April 13] UT, using the 3.5-m TNG The link with the comet of 1661 is reflector (+ high-resolution confirmed, but it seems to have spectrograph SARG; resolving been intrinsically brighter at that power 43000; spatial coverage return. An explanation is that the 26") with a narrow-band filter to comet's intrinsic brightness is isolate the sodium-D lines. Two variable, and this is clearly seen in long-slit spectra (one parallel and the current light curve, which the other perpendicular to the sun- shows a slow brightening over the comet vector) show cometary course of the apparition. Some sodium emissions clearly visible orbit computers suggest that the due to the comet's geocentric comet of 1532 is also associated velocity of -8.3 km/s. In the first with this comet and may be the spectrum, the sodium emissions primary component of a are clearly asymmetric with fragmentation which occurred respect to the slit center, over 1000 years ago, so it may be corresponding to the nuclear worth searching along the orbital region, extending to the edge of track for further fragments.

A. Lecacheux, Observatoire de the slit in the tail direction (about 4000 km). Even in the second A suggestion from Michael Paris; and N. Biver, European Mattiazzo is that the earth passed Space Agency, ESTEC, on behalf spectrum, a slight asymmetry is visible in the sodium emissions through the orbital plane of the of the Odin Solar System Topical comet around June 24-25 and this Team and of the Odin Team, with stronger intensity toward the southwest, suggesting the may have contributed to the report: "The Odin submillimetric apparent slow fade in brightness. space telescope observed water presence of a sodium jet that is most likely related to a dust lines in comet C/2002 C1 with a A naked eye observation on May high spectral resolution (80 m/s) feature. [IAUC 7914, 2002 June 2] 1.89 put it at around 4.5. An from Apr. 21.9 to 28.3 UT. The observation with 20x80B on May H_2O 110-101 line at 556.936 BAA COMET SECTION NEWSLETTER 18 THE COMET'S TALE

22.91 put it at 6.1. An observation 46 observations received give a and estimated it at 8.3 and still with 20x80B on May 31.94 put it preliminary light curve of m = 7.1 very strongly condensed. Jose at 6.4. Observations with 20x80 + 5 log d + 9.8 log r Aguiar observed it on May 17.89 Vixen binoculars in Cornwall and estimated it at 8.0 in 20x80B, under very dark skies in mid July 2002 EJ57 (P/LINEAR) A 19th with a very strongly condensed put the comet at around 9.5, but magnitude object discovered by coma. very diffuse. The diffuse nature LINEAR on March 13.20, and of the comet made it hard to pick noted by the Minor Planet Centre 73 observations received give a out in light polluted regions and to have an unusual orbit, has been preliminary light curve of m = 8.8 few observations were received found to be cometary. The object + 5 log d + 13.3 log r after mid August. is in a 17 year periodic orbit. Perihelion was in mid December 2002 H2 (LINEAR) A rapidly The comet has been very well at 2.6 AU and the object will fade. moving object reported by observed and it has become the [IAUC 7890, 2002 May 2] Its LINEAR has been found to be second most observed comet in orbit is affected by both Jupiter cometary. It was at perihelion on the Section files, after Hale-Bopp. and Saturn. March 23 at 1.63 AU and faded An apparently asteroidal object from around 13th magnitude. 1158 observations give an discovered by LINEAR was given Brian Marsden notes on MPEC aperture corrected preliminary the designation 2002 EJ_57 2002-L43 [2002 June 10] that the light curve of m = 6.1 + 5 log d + (observations on MPS 55777- "original" and "future" barycentric 6.7 log r The comet's absolute 55778). Additional observations values of 1/a are +0.004146 and magnitude has slowly varied by of the object were located during +0.003921 (+/- 0.000098) AU**- around two magnitudes over the routine processing at the Minor 1, respectively. The original value course of the apparition, though Planet Center, and these indicated implies that the comet is not a interestingly most of the variation that the orbit was unusual. The new visitor from the Oort cloud. took place when the comet was object was then placed on the outbound beyond 1 AU. NEO Confirmation Page, 2002 J4 (NEAT) S. Pravdo, E. resulting in CCD observations by Helin, and K. Lawrence, Jet J. Ticha and M. Tichy at Klet Propulsion Laboratory, report the (diffuse with coma diameter about discovery by NEAT, on CCD 10" on May 1.8 UT) and by R. H. images taken on May 13.45 UT McNaught at Siding Spring with the Palomar 1.2-m Schmidt (circular coma with diameter telescope, of a 18th mag comet about 7" on May 2.5) showing with nebulosity extending about cometary activity. [IAUC 7890, 5" toward the southwest. 2002 May 2] Following posting on the NEO Confirmation Page, additional observations obtained elsewhere on May 13.9 confirm the cometary nature: P. Kusnirak at Ondrejov (0.65-m reflector; m_1 = 18.3, faint 7" coma slightly elongated to the southwest); M. Tichy and M. Kocer at Klet (1.06- 2002 E2 (Snyder-Murakami) m KLENOT telescope; compact Brian Marsden notes on MPEC coma of diameter 16"); and L. 2002-L42 [2002 June 10] that the Kornos at Modra (0.6-m reflector; "original" and "future" barycentric m_1 = 16.6, coma diameter about values of 1/a are +0.000289 and - 15"). Additional observations 0.000180 (+/- 0.000023) AU**-1, made by LONEOS and LINEAR respectively. The original value on May 4, 7, and 8 were then implies that the comet is not a identified by the Minor Planet new visitor from the Oort cloud. Center staff. [IAUC 7899, 2002 2002 F1 (Utsunomiya) A May 13] The comet will not reach photograph submitted by Alex perihelion until October 2003, at Vincent shows the comet at 3.6 AU. It could reach 13th around 3rd magnitude on April 18, magnitude when brightest. significantly brighter than reported by visual observers. I 2002 J5 (LINEAR) An glimpsed the comet in very hazy apparently asteroidal 18th mag conditions on April 23.86, object discovered by LINEAR on estimating it at 4.5, with a 0.4 May 15.38 has been found to be degree long tail. On May 1.87 I slightly diffuse with a coma estimated it at 6.3 in my new diameter of about 10" on CCD Vixen 20x80B, surprisingly easy, images taken by M. Tichy and M. and with the Pleiades a beautiful Kocer with the 1.06-m reflector at sight just below the comet. Klet on May 16.0 UT. [IAUC Antonio Giambersio made it 5.2: 7904, 2002 May 18] on May 1.79 in 16x70B. The comet is distant and will Alexandre Amorim observed the reach perihelion at 5.7 AU in comet with 20x80B on May 11.90 September 2003. BAA COMET SECTION NEWSLETTER 2000 October 19

Brian Marsden notes on MPEC discovered by Tim Spahr at the 0.7 AU from the planet in 1977. It 2002-L45 [2002 June 10] that the Whipple observatory on 2002 approached to 0.15 AU of the "original" and "future" barycentric May 7.17. It is in a 5.5 year orbit, Earth in 1986. values of 1/a are +0.000010 and - with perihelion at 1.83 AU and an 0.000036 (+/- 0.000028) AU**-1, eccentricity of 0.41. It is A/2002 KL6 (NEAT) is an respectively, suggesting that this approaching perihelion and will asteroid, of 17th magnitude, is a "new" comet. remain of similar brightness. discovered by NEAT on 2002 [MPEC 2002-K21, 2002 May 20] May 27.42. It is in a 4.7 year 2002 JN16 (P/LINEAR) An The orbit is typical of a Jupiter orbit, with perihelion at 1.04 AU apparently asteroidal object of family comet, and the object was and an eccentricity of 0.63. It is at 18th mag reported by LINEAR on 0.6 AU from the planet in 1950. perihelion in July and will May 9.28, designated 2002 brighten a little. [MPEC 2002- JN_16, and having an unusual 2002 K1 (NEAT) K. Lawrence, K70, 2002 May 29] The orbit is orbit (e.g., MPEC 2002-J42) has E. Helin, and S. Pravdo, Jet typical of a Jupiter family comet, been found by C. A. Trujillo, Propulsion Laboratory, report the though there have been no recent California Institute of discovery of a comet with a tail close approaches. The object can Technology, to be cometary about 8" long toward the approach the earth to within 0.07 (coma extended 10"-15" from the southwest (and m_2 = 19.4-19.6) AU. nuclear condensation in p.a. 270 on images taken with the 1.2-m deg) on images taken on May NEAT telescope at Haleakala on A/2002 KJ8 (NEAT) is an 17.2 UT as part of a program by May 16.55. Confirming CCD asteroid, of 20th magnitude, M. Brown and himself with the images by E. S. Barker at discovered by NEAT on 2002 1.2-m Schmidt telescope at McDonald Observatory (0.76-m May 18.23. It is in a 6.1 year Palomar. At Trujillo's request, J. reflector) show a 15" tail toward orbit, with perihelion at 1.37 AU Tonry obtained images of 2002 the southwest. [IAUC 7902, 2002 and an eccentricity of 0.59. It is at JN_16 through clouds with the May 17] perihelion at the end of July and University of Hawaii 2.2-m The comet is distant and just past will brighten a little. [MPEC reflector at Mauna Kea on May perihelion at 3.2 AU. 2002-K74, 2002 May 31] The 22.35 that show a similar orbit is typical of a Jupiter family appearance and m_1 = 17.2. 2002 K2 (LINEAR) Another comet and it approached to 0.24 [IAUC 7907, 2002 May 22] apparently asteroidal LINEAR AU in 1871. discovery of 18th mag, found on Perihelion is at the end of July at May 16.37, has also been found to 2002 L9 (NEAT) An object of 1.8 AU and the object is in a 6.6 be cometary on Klet CCD images 18th mag originally reported as year periodic orbit. It will that show a compact coma of asteroidal on NEAT CCD images brighten a little, but is unlikely to diameter about 7"-8" on May 16.9 taken at Palomar on June 13.41 exceed 17th mag. It is a Jupiter and 18.0 UT. [IAUC 7904, 2002 was posted on the NEO family comet. May 18] Confirmation Page due to its The comet is faint and distant. It unusual orbit. S. Pravdo later A/2002 JE109 (LINEAR) is an will reach perihelion at 5.2 AU suggested the object was asteroid, of 19th magnitude, and is just past perihelion. It will cometary, in particular on July 2 discovered by LINEAR on 2002 not brighten significantly noting a central condensation of May 11.30. It is in a 6.1 year diameter 3" surrounded by a orbit, with perihelion at 1.68 AU 2002 K4 (NEAT) S. Pravdo, E. spherical nebulosity of diameter and an eccentricity of 0.50. It is Helin, and K. Lawrence, Jet about 8". [IAUC 7931, 2002 July close to perihelion and will fade. Propulsion Laboratory, report the 2] [MPEC 2002-K11, 2002 May 17] discovery of a 19th mag comet It will reach perihelion in 2004 at The orbit is typical of a Jupiter (with nuclear condensation of 7 AU and will brighten a little family comet, though there have diameter about 4" and tail when nearer perihelion. been no recent approaches to extending about 10" to the Jupiter. The perihelion distance southwest) on NEAT images A/2002 LV (LINEAR) is an has varied from 1.5 to 1.7 AU taken at Haleakala on May 27.51 asteroid, of 18th magnitude, over the last few hundred years, UT, with confirming NEAT discovered by LINEAR on 2002 but there have been no significant images taken at Palomar on May June 1.37. It is in a 5.1 year orbit, changes to the angular elements. 28. [IAUC 7909, 2002 May 28] with perihelion at 0.92 AU and an It will reach perihelion in July, at eccentricity of 0.69. It is at A/2002 JC68 (LINEAR) is an 2.8 AU. It is periodic, with a perihelion in late August and will asteroid, of 19th magnitude, period of around 64 years. It will brighten to 15th magnitude. discovered by LINEAR on 2002 brighten a little. [MPEC 2002-L14, 2002 June 3] May 7.32. It is in a 5.3 year orbit, The orbit is typical of a Jupiter with perihelion at 1.39 AU and an A/2002 KK3 (LONEOS) is an family comet, though the high eccentricity of 0.54. It reaches asteroid, of 19th magnitude, inclination (31 degrees) keeps it perihelion in September and will discovered by LONEOS on 2002 relatively far from the planet. The fade. [MPEC 2002-L27, 2002 May 18.28. It is in a 5.4 year more distant encounters are June 7] The orbit is typical of a orbit, with perihelion at 1.08 AU slowly changing the orbital Jupiter family comet, though there and an eccentricity of 0.65. It is elements and are currently tending have been no recent approaches to close to perihelion and will to reduce the inclination. It is a Jupiter. remain at a similar brightness. potentially hazardous object and [MPEC 2002-K24, 2002 May 20] can approach to 0.027 AU of the A/2002 JW115 (Spahr) is an The orbit is typical of a Jupiter Earth at the descending node. This asteroid, of 20th magnitude, family comet and the object was BAA COMET SECTION NEWSLETTER 20 THE COMET'S TALE year it approaches within 0.14 AU empty water bottle. He reported Narrow-band [M] and [N] on July 29. the details to the CBAT, but it magnitudes were 9.7 and 4.4, wasn't until five days later that he respectively, both +/- 0.1." [IAUC A/2002 LJ27 (LINEAR) is an finally received confirmation of 7950, 2002 August 8] asteroid, of 19th magnitude, his find. In addition to this comet, discovered by LINEAR on 2002 Sebastian has discovered around a The latest orbit on MPEC 2002- June 8.31. It is in a 6.0 year orbit, two dozen comets on SOHO R48 has a note from Brian with perihelion at 1.67 AU and an LASCO images, but these all bear Marsden that 'the "original" and eccentricity of 0.49. It is close to the name SOHO. "future" barycentric values of 1/a perihelion and will fade. [MPEC are -0.000694 and -0.000230 (+/- 2002-L62, 2002 June 13, 5-day 0.000054) AU**-1, orbit] The orbit is typical of a respectively.'[2002 September 11] Jupiter family comet, though there It is somewhat unusual for a have been no recent approaches. comet to have a negative "original" value for 1/a and this is A/2002 MS3 (NEAT) is an one of the largest on record. It is asteroid, of 19th magnitude, possible that 'non gravitational' discovered by NEAT on 2002 effects should be applied to the June 30.24. It is in a 7.6 year comet's orbit. orbit, with perihelion at 0.92 AU and an eccentricity of 0.76. It is at An image by Cliff Meredith on August 19 After my return from the ACM perihelion in early September and meeting in Berlin (where I met up will brighten a little. [MPEC On July 22, a report of an with Sebastian and Maik Meyer) I 2002-N05, 2002 July 1] The orbit apparent visual comet discovery was able to observe the comet on is typical of a Jupiter family of a 12th mag comet on July August 4.9. I estimated it at 9.5 in comet, though there have been no 22.00 was received from the Thorrowgood refractor x40, recent close approaches to the Sebastian Hoenig, Dossenhiem, with a 3' coma and DC3. The planet. Germany. The object clearly early observations suggested that Further observations show that it showed motion to the north. Due the comet was brightening quite is actually in an Apollo type orbit. to poor initial positions and bright rapidly as several reports on moon, attempts to recover the August 6 put the comet as bright A/2002 MT3 (NEAT) is an object visually by A. Hale as 8th magnitude. A photograph asteroid, of 19th magnitude, (Cloudcroft, NM) and Hoenig taken on August 8.83 by Toni discovered by NEAT on 2002 were unsuccessful. On July 27, S. Scarmato shows a green coma, June 30.24. It is in a 4.5 year Nakano (Sumoto, Japan) reported characteristic of Swan band orbit, with perihelion at 0.89 AU that K. Kadota (Ageo, Saitama, emissions. I observed it with and an eccentricity of 0.67. It was Japan), following a request by A. 20x80 binoculars on August 10.91 at perihelion in late April. It is a Nakamura (Kuma, Ehime, Japan), and made it 7.8. potentially hazardous object and successfully imaged a comet can approach within 0.03 AU of while searching for the object the Earth [MPEC 2002-N06, 2002 reported on July 22. Additional July 1] The orbit is typical of a observations were received after Jupiter family comet and it the comet was posted on the NEO approached within 0.4 AU in Confirmation Page. [IAUC 7939, 1928. 2002 July 27]

2002 O4 (Hoenig) The discovery of this was announced during the ACM meeting, which was particularly appropriate, as the discoverer is German. This was the first comet to be discovered from Germany since 1946 and it was an accident! Sebastian An image by Denis Buczynski on Hoenig is a keen amateur September 10 astronomer and after a long period of cloudy weather a clear spell The comet's brightness then drew him out to a dark sky An image by Martin Mobberley on stalled and it did not significantly location. Whilst scanning for September 3.87 with his 0.3m LX200. brighten any further. A globular clusters in the suggestion from Michael Andromeda region with his 25-cm Sitko, Lynch, Russell, Hammel Mattiazzo is that the earth passed LX200, an unexpected fuzz and Polomski report similar through the orbital plane of the caught his eye. He knew that spectroscopy of comet C/2002 O4 comet around August 13-14 and there wasn't supposed to be on Aug. 1.54 UT: "The infrared this may have given the apparent anything in the area, but hadn't flux peaked near 10 microns, rapid rise in brightness. come prepared for any serious suggesting a temperature of Observations up to the equinox observing. He took the around 280 +/- 20 K (equilibrium suggested that the comet was approximate RA and Dec from his blackbody temperature = 243 K). fading slightly. Further roughly set-up GoTo system and There was a silicate-emission observations reported on the wrote the co-ordinates along with feature between about 8.5 and internet towards the end of the a rough sketch on the label of an 11.5 microns extending about 20 month suggest a more dramatic percent above the continuum. BAA COMET SECTION NEWSLETTER 2000 October 21 fade and it seems unlikely that it would brighten. It had perihelion instrument on the SOHO will survive perihelion, unless it at 0.5 AU in early September. spacecraft on July 25 and 27 UT. experiences an outburst Prediscovery images were found comparable to 2000 WM1. on images taken as early as July 13. Visual confirmation has been reported by A. Hale, Cloudcroft, New Mexico, with a 0.20-m reflector (coma diameter 4'; magnitude measurement hampered by twilight, moon and clouds). CCD frames taken by J. Broughton, Reedy Creek, Australia, with a 0.25-m reflector also confirm the object's cometary nature. [IAUC 7944, 2002 August 1]

130 observations give a preliminary light curve of m = 8.4 + 5 log d + 5.4 log r Alternatively a slightly better fit is given by a linear type of light curve, peaking some 30 days before perihelion. Akimasa Nakamura provides the 2002 O5 (P/NEAT) S. Pravdo following discovery report: and K. Lawrence, Jet Propulsion Masayuki Suzuki posted the Laboratory, report the discovery discovery circumstances of of a 16th mag comet (with nuclear C/2002 O6 to the comet-obs condensation of diameter about 6" mailing list (in Japanese). and tail extending 12" to the According to that, although he is a southwest) on NEAT images Comet 2002 O6 (SWAN) imaged by frequent visitor to the SWAN Michael Jager on September 13.125. The taken at Haleakala on July 30.25 webpage (and has checked images image is a composite of 6.5 and 5.5 min UT. After the object was placed time to time since this spring), his exposures on a 250/450 mm Schmidt on the NEO Confirmation Page, discovery of O6 was accidental. camera using hypered TP2415. The faint confirmation of cometary activity Inspired by Sebastian's discovery, cigar shaped coma is typical of a was reported by: R. Fredrick, K. he downloaded SWAN images disintegrating comet. Smalley, and R. Trentman, taken on 25th and 27th of July, to Louisburg, Kansas, with a 0.75-m see whether he could find C/2002 Observations in early August reflector (tail 40" long in p.a. 130 O4 or not. He found TWO showed that it was slowly deg); P. M. Kilmartin, Mt John moving objects: dimmer one was brightening and it reached around Observatory, New Zealand, with a C/2002 O4, and the brighter one mag 6. I observed it after a long 0.6-m reflector (short tail in about looked like C/2001 Q4 (NEAT). meteor watch on August 12/13 p.a. 130 deg); and R. H. But, he noted the latter should and found it an easy object in McNaught and G. J. Garradd, have been much fainter because 20x80B. Reports by Bjorn Siding Springs Observatory, Q4 was around 16 mag.... it might Granslo at the end of August Australia, with a 1.0-m reflector be a new comet! He considered a show that it has faded (tail 13" long in p.a. 125 deg). possibility to observe it by significantly to around 7.5. [IAUC 7942, 2002 July 31]. himself on the night of his Observations by myself in early discovery (July 31th), but gave up September suggest that the fade is The preliminary orbit suggests due to bad weather and its continuing, with the comet at mag that it is in a short period orbit position (way out of his 8 with P around 5 years and is near observable sky). So, he sent his perihelion. It is intrinsically very discovery report to the CBAT faint (H0=19) and will fade. The without confirmation. (He is an orbital period is the third shortest astrometrist at code 347, BTW.) of current P/ comets. At a He also noted the comet was favourable return it can pass 0.2 visible on the images taken on 13, AU from the Earth. 16, 18, 20th as well (faint, though), and later measured their 2002 O6 (SWAN) This positions and sent them to the interesting comet was discovered CBAT in response to the request by Masayuki Suzuki using real- by Carl Hergenrother. time SOHO-SWAN data and is the first SWAN discovery to be M. Suzuki, Utsunomiya, Tochigi, observed from the ground. The Japan, reports the discovery of a first orbit showed that the comet comet on publicly accessible was passing close to the earth and images taken with the SWAN BAA COMET SECTION NEWSLETTER 22 THE COMET'S TALE

The preliminary orbit suggests revolutions. At a favourable 56 observations give a that it is a distant object past return it could reach 7m. preliminary light curve of m = 9.2 perihelion and will fade. + 5 log d + 4.1 log r We may pick it up in November A/2002 PD43 (NEAT) is an as it brightens to 10th magnitude 2002 O7 (LINEAR) An asteroid, of 17th magnitude, and we will be able to follow it apparently asteroidal, 20th mag, discovered by NEAT at Paolomar into the New Year as it continues object reported by LINEAR on on 2002 August 7.45. to move north. It is an evening July 29.17 UT has been found to Prediscovery images were taken object, but its solar elongation be cometary by A. Boattini on only hours earlier by W Yeung. It decreases from 80° in November CCD images taken with the 0.60- is in a 4.2 year orbit, with to 50° at the end of the year. It m Schmidt at Campo Imperatore perihelion at 0.11 AU and will not reach perihelion until on Aug. 2.9 and by J. Ticha and aphelion at 5.07 AU and is 2003. By October it is moving M. Tichy with the 0.57-m classied as an Apollo type north-eastwards in Capricornus telescope at Klet on Aug. 4.9 asteroid. It is a potentially and ends the year in Aquarius. (comet slightly diffuse with a hazardous object and can coma of diameter 8"). [IAUC approach within 0.035 AU of the 2002 Q5 (LINEAR) LINEAR has 7949, 2002 August 5] Earth. It was at perihelion in mid discovered another comet. It June. [MPEC 2002-P51, 2002 reaches perihelion in November, The comet does not reach August 12] but unfortunately it is on the perihelion until September 2003, opposite side of the Sun to the when it may reach 6th magnitude. 2002 Q1 (P/Van Ness) Michael Earth at the time and will not get At its brightest it will be a Van Ness of the LONEOS team brighter than 15th magnitude. southern hemisphere object, but discovered a 16th magnitude should be visible as a telescopic comet on 2002 August 17.44. It is 2002 R2 (155P/Shoemaker) object from 2003 March to 2004 periodic with a period of around (1986 A1) has been recovered by January. [MPEC 2002-P13, 2002 6.6 years and is past perihelion. It T Oribe and A Nakamura at 18th August 5] will fade. mag. The correction to the prediction on MPC 34423 is 2002 O8 (P/NEAT) K. Lawrence, 2002 Q2 (LINEAR) and 2002 Delta(T) = -0.14 day. It is making Jet Propulsion Laboratory, reports Q3 (LINEAR) LINEAR has its first return since discovery. It the discovery of a 17th mag comet found a pair of comets, moving on will be quite faint, around 14-13th (with nuclear condensation of parallel tracks in the same field. magnitude in November and does diameter about 6" and a tail The brighter (Q2) is about 17th not get much brighter by the time extending about 10" to the west) mag and Q3 is a couple of mags it reaches opposition in February on NEAT images obtained on fainter. The preliminary orbit 2003. It moves eastwards from July 29.32 UT (discovery suggests that they are just past Cancer into Leo at the end of the observation appears below). perihelion in a high inclination year. Confirmation of cometary activity orbit. BAA observer Stephen was reported by A. C. Gilmore Laurie was able to provide 2002 R3 (LONEOS) is a distant and P. M. Kilmartin on CCD confirming astrometry within 24 comet that will reach perihelion images taken with the 0.6-m hours of the discovery. Maik next year, however it will not Meyer points out that the brighten much from its present reflector at Mt John University th Observatory on Aug. 4.4 (faint preliminary elements are similar 17 magnitude. tail 40" in p.a. 255 deg). to those of 1994 N1 (Nakamura- Prediscovery observations have Nishimura-Machholz). Some A/2002 RC118 (LINEAR) is an recent observations are putting Q2 asteroid, of 19th magnitude, been identified in NEAT data th from July 16.5, LINEAR data at around 13 magnitude. discovered by LINEAR on 2002 from July 5.4 and Spacewatch September 6.34. It is in a 5.2 year data from 2001 May 22.3 and 2002 Q4 (154P/Brewington) has orbit, with perihelion at 1.28 AU June 11.2. [IAUC 7949, 2002 been recovered at 17th mag by F. and an eccentricity of 0.57. It is at August 5] Artigue, H. Cucurullo, and G. perihelion in mid November and Trancredi at the Observatorio will brighten to 17th mag. [MPEC It is in a periodic orbit of 8 years Astronomico Los Molinos, 2002-R40, 2002 September 8, 3- and perihelion at 3.2 AU and is a Montevideo. The correction to the day orbit] The orbit is typical of a Jupiter family comet. It will fade. prediction on MPC 40670 is Jupiter family comet, though there Delta(T) = +0.52 day. have been no recent approaches. 2002 P1 (NEAT) S. Pravdo, K. Lawrence and E. Helin, Jet The comet is making its first A/2002 RP120 (LONEOS) is an Propulsion Laboratory, report the return in 2003 since its discovery asteroid, of 17th magnitude, NEAT team's discovery with the in 1992. It was discovered by discovered by LONEOS at Lowell 1.2-m Schmidt telescope at Howard J Brewington of Observatory on 2002 September Palomar of a 19th mag comet with Cloudcroft, New Mexico, as a 4.41. The orbit is retrograde, with a 7" tail in p.a. 235 deg on August small diffuse 10m object on a period of around 300 years and 7.39. Confirmation of the object's August 28.41 using a 0.40-m perihelion distance at 2.47 AU, diffuse appearance has been reflector x55. This was his fourth with aphelion over 90 AU from provided by G. Hug, Farpoint discovery and his second periodic the Sun. It reaches perihelion in Observatory: [IAUC 7950, 2002 one. The comet is in a Jupiter early October, when it may August 8] crossing orbit, but has not brighten to 16th mag. [MPEC approached the planet for several 2002-R43, 2002 September 10, 6- day orbit] The orbit is more BAA COMET SECTION NEWSLETTER 2000 October 23 typical of a long period comet, September 12, 2-day orbit] The until the end of the year. though so far there is no sign of orbit is typical of a Jupiter family cometary activity. comet and can approach both For the latest information on Jupiter and the Earth. discoveries and the brightness of A/2002 RA126 (NEAT) is an comets see the Section www asteroid, of 20th magnitude, 2002 S1 (P/Skiff) was found by page: discovered by NEAT at Palomar Brian Skiff during the course of http://www.ast.cam.ac.uk/~jds or on 2002 September 11.14. It is in LONEOS survey work. The 18th the CBAT headlines page at a 5.2 year orbit, with perihelion at magnitude comet is past http://cfa- 1.04 AU and an eccentricity of perihelion. It is in a periodic orbit www.harvard.edu/cfa/ps/Headline 0.65. It is past perihelion and will of around 8.3 years, and will s.html fade. [MPEC 2002-R61, 2002 remain at its present brightness 2002 EDGAR WILSON AWARDS

The Smithsonian Astrophysical for C/2000 W1 (Utsunomiya- first return of this comet to the Observatory (SAO), part of the Jones). Ikeya became world- inner solar system in 341 years, Harvard-Smithsonian Center for famous in the 1960s for a string of since it was last observed in 1661. Astrophysics in Cambridge, five comet discoveries between Carefully made observations in Massachusetts, has announced the 1963 and 1967, with comet February and March 1661 by the recipients of the 2002 Edgar C/1965 S1 (Ikeya-Seki) becoming Polish astronomer Johannes Wilson Award for the discovery the brightest comet of the last Hevelius have allowed of comets by amateurs during the century -- visible in broad astronomers to confirm that the calendar year ending June 10. daylight to the unaided eye as it two apparitions belong to the The award was set aside as part of skimmed closely by the sun's same comet, though for centuries the will bequeathed by the late surface in October 1965. it was speculated erroneously that businessman Edgar Wilson of the 1661 comet might be identical Lexington, Kentucky, and The six visual discoveries of this with a comet seen in 1532. administered by the SAO. The past year involved four different Comet 2002 C1 is now the comet following seven discoverers will comets and represent the most with the longest orbital period that receive plaques and a cash award: new comets discovered by visual has been definitely seen at two or observers since 1994. Automated more returns to perihelion (closest Vance Avery Petriew of Regina, CCD searches with large approach to the sun). Saskatchewan, Canada, for his professional telescopes have visual discovery of comet P/2001 dominated comet discovery since In 2001, there were only two Q2 on 2001 August 18. 1998. Utsunomiya's discovery recipients of the Award, for their Kaoru Ikeya of Mori, Shuchi, was made with large 25x150 independent visual discoveries of Shizuoka, Japan, and Daqing binoculars. The other discoveries a single comet (Albert Jones of Zhang, Kaifeng, Henan province, were all made with moderate- New Zealand and Syogo China, for their independent sized reflecting telescopes having Utsunomiya). Of the 20 Award visual discoveries of comet mirrors with diameters ranging recipients in the first four years, C/2002 C1 on 2002 February 1. from 25 to 50 cm. twelve have been for visual Douglas Snyder of Palominas, discoveries, seven for discoveries Arizona, and Shigeki Murakami Yeung's discovery image was from CCD images, and one for a of Matsunoyama, Niigata, Japan, obtained on 2002 January 21, but discovery from a photograph. for their independent visual he reported the object initially as The countries with the most discoveries of comet C/2002 E2 stellar in appearance and it was recipients so far are the United on 2002 March 11. given a minor-planet (rather than States (5), Japan (4), and Syogo Utsunomiya of Minami- cometary) designation; CCD Australia (4). In years when there Oguni, Aso, Kumamoto, Japan, images taken by Timothy Spahr at are no eligible comet discoverers, for his visual discovery of comet the SAO station on Mount the Award will be made instead to C/2002 F1 on 2002 March 18. Hopkins in Arizona in early May amateur astronomers judged by William Kwong Yu Yeung of showed that P/2002 BV was the Central Bureau for Benson, Arizona for his charge- indeed cometary with a faint tail, Astronomical Telegrams (CBAT) coupled-device (CCD) electronic- and Yeung's object was to have made important camera discovery of comet announced as a comet on May 9 contributions toward observing P/2002 BV. (IAU Circular 7896). comets or promoting an interest in the study of comets. Observers Ikeya and Utsunomiya The brightest comet of the bunch, have had their names attached to C/2002 C1 (Ikeya-Zhang), David A. Aguilar & Christine comets previously. Comet became a faint naked-eye object Lafon, Public Affairs, Harvard- C/2002 F1 was Utsunomiya's in March and April for northern- Smithsonian Center for third named comet; he also won hemisphere observers. It is of Astrophysics the Edgar Wilson Award in 2001 special interest because it is the Comet Prospects for 2003

2003 sees the return of 16 59th predicted return at the end of may reach binocular visibility at periodic comets. The brightest of the year and may reach 6th the end of the year. Several other the year is predicted to be magnitude. 2001 Q4 (NEAT) long-period comets discovered in 2P/Encke, which is making its reaches perihelion in 2004 and previous years are still visible. BAA COMET SECTION NEWSLETTER 24 THE COMET'S TALE

Theories on the structure of elongation is poor and it is the nodes. The pre 1850 orbit is comets suggest that any comet unlikely to be seen this year. very similar to that of could fragment at any time, so it 42P/Neujmin 3 and it is likely that is worth keeping an eye on some 29P/Schwassmann-Wachmann they are fragments of the same of the fainter periodic comets, is an annual comet that has parent. The comet has a relatively which are often ignored. This frequent outbursts and seems to favourable return and just reaches would make a useful project for be more often active than not at 14th magnitude, however it lies CCD observers. As an example the moment, though it rarely gets south of the equator and will be 51P/Harrington was observed to brighter than 12m. It begins the difficult to observe from the UK. fragment in 2001. Ephemerides year in Capricornus, but spends for new and currently observable most of the year in Aquarius, 65P/Gunn was discovered in comets are published in the reaching opposition at the 1970 after a perturbation by Circulars, Comet Section beginning of September. The Jupiter in 1965 had reduced the Newsletters and on the Section, comet is an ideal target for those perihelion distance from 3.39 to CBAT and Seiichi Yoshida's web equipped with CCDs and it should 2.44 AU. In 1980 two pre- pages. Complete ephemerides be observed at every opportunity. discovery images were found on and magnitude parameters for all UK based observers should be Palomar plates taken in 1954. comets predicted to be brighter able to follow it throughout the The comet can be followed all than about 18m are given in the second half of the year. round the orbit as it has a International Comet Quarterly relatively low eccentricity of 0.32. Handbook; details of subscription 30P/Reinmuth was at perihelion At the last return in 1996 it to the ICQ are available from the last year, and is a little brighter at reached 13th magnitude and it will comet section Director. The the start of this year, although do a little better this time, as it is section booklet on comet only 14th magnitude. Best seen in at opposition when at perihelion. observing is available from the the morning sky, it reaches It will be at moderate southern BAA office or the Director. opposition in March, but by then declination throughout the is fading quite rapidly. The comet apparition and is essentially This year sees comet 2P/Encke's was discovered during the course unobservable from the UK. 59th observed return to perihelion of a regular photographic asteroid since its discovery by Mechain in survey by Karl Reinmuth at 66P/du Toit has only been 1786. The orbit is quite stable, Heidelberg Observatory on a observed at alternate returns and and with a period of 3.3 years photograph exposed on 1928 its last return in 1988 was about apparitions repeat on a 10-year February 22.96. If the comet gets the worst possible. It was cycle. This year the comet is well as bright as predicted this could discovered by Daniel du Toit at seen from the Northern be the best return since the the Boyden Observatory in South Hemisphere prior to perihelion, comet's discovery. Africa on 1944 May 16. The which is in late December. The discovery return was a good one, comet tracks through Andromeda 43P/Wolf-Harrington does not with the comet approaching to during October and early reach perihelion until 2004, but it within 0.5 AU of the Earth, and November, then accelerates gets to 14th magnitude in the comet reached 10th magnitude. southwards through Cygnus and September and should be 13th It was not found at the 1959 begins December in Ophiuchus. magnitude at the end of the year. return, nor was it initially found in The comet might be observable It is favourably placed in the 1974, however in January 1975 a from October until early evening sky and CCD observers further inspection of search plates December, when it could be 6th should certainly have a go at taken ten months previously magnitude. This magnitude may following the comet. This will be revealed a diffuse image of the however be optimistic as its tenth observed return, which comet. This return is moderately observations from the SOHO was discovered in 1924, then lost favourable, and the comet could spacecraft in 2000 showed that it until 1951. The comet is in a reach 13th magnitude, however, as suddenly brightened after chaotic orbit, and made a close at the discovery return, it will perihelion, by which time it will approach to Jupiter in 1936 which essentially be a Southern be at a poor elongation. A reduced its perihelion distance Hemisphere object. possible explanation of this from 2.4 to 1.6 AU. It made an behaviour is that Encke has two exceptionally close (0.003 AU) 81P/Wild is a new comet that active regions, an old one with approach to Jupiter in 1841, made a very close (0.006 AU) declining activity, which operates which switched its previous approach to Jupiter in September prior to perihelion and a recently perihelion distance into the new 1974. Prior to this it was in a 40- activated one present after aphelion distance. year orbit that had perihelion at 5 perihelion. There is, however, AU and aphelion at 25 AU. The little evidence for a secular fading 53P/Van Biesbroeck is an comet was discovered by Paul in the archive of BAA interesting object. George van Wild with the 40/60-cm Schmidt observations of the comet. The Biesbroeck discovered it at at Zimmerwald on 1978 January comet is the progenitor of the Yerkes observatory in September 6. The Stardust spacecraft is due Taurid meteor complex and may 1954. Stan Milbourn and George to visit the comet in 2004 and be associated with several Apollo Lea calculated the best recovery recover material for return to asteroids. orbit and the comet was duly earth in 2006. The comet reaches recovered in May 1965. Back perihelion in September, but 22P/Kopff reached perihelion at calculating the orbit shows that it unfortunately the elongation is the end of 2002 and although it is made a moderately close approach very poor and the comet will be near its brightest, the solar to Jupiter in 1850, which reduced difficult to observe at this return. q from 2.7 to 2.4 AU and reversed BAA COMET SECTION NEWSLETTER 2000 October 25

95P/Chiron is an unusual comet approach to Jupiter in mid 1987. in the New Year after its in that it is also asteroid 2060. It The comet is at perihelion in December perihelion. reaches 17m when at opposition in January, but is poorly placed for July in Sagittarius. CCD V viewing from the UK. It 154P/Brewington makes its first magnitudes of Chiron would be of brightens from 13th magnitude at return since its discovery in 1992. particular interest as observations the beginning of the year to 12th It was discovered by Howard J show that its absolute magnitude magnitude in April as it nears Brewington of Cloudcroft, New varies erratically. It was at opposition but is a long way Mexico, as a small diffuse 10m perihelion in 1996 when it was south. It remains brighter than object on August 28.41 using a 8.5 AU from the Sun and will be 13th magnitude until July. 0.40-m reflector x55. This was nearly 19 AU from the Sun at his fourth discovery and his aphelion in around 50 years time. 123P/West-Hartley was second periodic one. The comet discovered by Richard West on an is in a Jupiter crossing orbit, but 116P/Wild was discovered on ESO survey plate taken on March has not approached the planet for 1990 January 21.98 by Paul Wild 14 and independently by Malcolm several revolutions. At a with the 0.40-m Schmidt at the Hartley on a UK Schmidt plate favourable return it could reach Zimmerwald station of the Berne taken on May 28. The comet has 7m, but this return is not Astronomical Institute at a made no recent close approaches particularly favourable. It is an photographic magnitude of 13.5. to Jupiter. It reached between 13th evening object, of around 10 - 11th At its brightest the comet only and 14th magnitude at the last magnitude, but its solar reached 12m, but it was return in 1996. It should achieve elongation decreases from 50º at surprisingly well observed. The a similar brightness this time the beginning of the year and we comet was perturbed into its round, but is at its brightest early will loose it in the March twilight. present orbit after a close Comets reaching perihelion in 2003

Comet T q P N H1 K1 2001 RX14 (LINEAR) Jan 18.8 2.06 6.5 10.0 116P/Wild Jan 21.6 2.17 6.48 2 1.2 25.3 79P/du Toit-Hartley Feb 15.3 1.23 5.27 3 14.0 15.0 154P/Brewington Feb 19.4 1.59 10.66 1 8.5 13.5 P/Tritton Mar 6.0 1.43 6.32 1 12.5 10.0 2001 YX127 (P/LINEAR) Mar 6.9 3.42 8.54 12.5 10.0 65P/Gunn May 11.9 2.45 6.80 6 5.0 15.0 25D/Neujmin May 26.4 1.27 5.38 2 10.5 10.0 127P/Holt-Olmstead Jun 12.5 2.16 6.34 2 14.0 10.0 2002 R3 (LONEOS) Jun 14.9 3.86 8.5 10.0 36P/Whipple Jul 6.7 3.09 8.51 10 8.5 15.0 2001 HT50 (LINEAR-NEAT) Jul 8.8 2.80 4.5 10.0 118P/Shoemaker-Levy Jul 16.8 2.01 6.49 2 8.7 10.0 100P/Hartely Aug 18.0 1.98 6.29 3 8.9 15.0 66P/du Toit Aug 28.2 1.27 14.70 2 12.0 9.5 94P/Russell Aug 29.2 2.23 6.58 3 9.0 15.0 2002 J5 (LINEAR) Sep 19.3 5.73 11.0 5.0 2002 O7 (LINEAR) Sep 20.3 0.89 6.5 10.0 81P/Wild Sep 25.9 1.59 6.40 4 6.9 11.4 2002 J4 (NEAT) Oct 3.2 3.63 5.5 10.0 53P/Van Biesbroeck Oct 9.4 2.42 12.52 4 8.0 15.0 123P/West-Hartley Dec 9.1 2.13 7.58 2 11.5 10.0 2P/Encke Dec 29.9 0.34 3.30 58 11.0 15.0

The date of perihelion (T), perihelion distance (q), period (P), the number of previously observed returns (N) and the magnitude parameters H1 and K1 are given for each comet.

Note: m1 = H1 + 5.0 * log(d) + K1 * log(r)

155P/Shoemaker reaches discovery. It will be quite faint, moves northwards in the sickle of perihelion in 2002 December, and around 14-13th magnitude when it Leo. is making its first return since is at opposition in February. It BAA COMET SECTION NEWSLETTER 26 THE COMET'S TALE

Several recently discovered (LINEAR) should come within 2001 Q4, which may become parabolic comets will be visible reach of visual observers in brighter than 3rd magnitude at during 2003. 2001 HT50 March and UK observers will be perihelion. Several periodic (LINEAR) will be a morning able to follow it until mid year. It comets have favourable returns, object of around 12th magnitude at continues brightening, but is best but they will all be telescopic the start of the year, but it quickly placed for Southern Hemisphere objects. moves towards opposition. It observers. Brightest after its brightens a little, but becomes September perihelion, it should References and sources poorly placed for observation still be an easy binocular object after April. It reaches perihelion when it passes within a few Nakano, S. and Green D. W. E., whilst in solar conjunction, but re- degrees of the South Pole in Eds, International Comet emerges towards the end of November. Quarterly 2002 Comet Handbook, August at around 11th magnitude. (2001). The earth continues to approach it Several other comets are at Shanklin, J. D., Observing Guide until October, when it is perihelion during 2003, however to Comets, 2nd edition (2002) fractionally brighter, and it then they are unlikely to become bright Marsden, B. G. Catalogue of fades slowly to the end of the enough to observe visually or are Cometary Orbits, 14th edition, year. 2001 Q4 (NEAT) doesn't poorly placed. 94P/Russell, IAU CBAT, (2001). reach perihelion until 2004, but 100P/Hartley, 118P/Shoemaker- Kronk, G. W., Cometographia, will be brightening into visual Levy and 127P/Holt-Olmstead Cambridge University Press, range at the end of 2003. It is have unfavourable returns 2002 J4 (1999) and however a Southern Hemisphere (NEAT) is unfavourably placed http://www.cometography.com. object and UK observers will for viewing from the UK, whilst Belyaev, N. A., Kresak, L., have to wait until it heads north in 36P/Whipple, 79P/du Toit- Pittich, E. M. and Pushkarev, A. 2004. 2001 RX14 (LINEAR) will Hartley, 2001 YX127 (LINEAR), N., Catalogue of short Period be around 10th magnitude at the 2002 J5 (LINEAR) and 2002 R3 Comets, Bratislava (1986). start of the year. It is a fraction (LONEOS) are intrinsically faint brighter in February, just after or distant comets. Ephemerides Jonathan Shanklin perihelion, and only fades slowly, for these can be found on the so we will be able to follow it CBAT WWW pages. The Comet's Tale is produced by until it sinks into the twilight in 25D/Neujmin has not been seen Jonathan Shanklin, with thanks to June. Initially it is well placed on since 1926 and P/Tritton has not the British Antarctic Survey and the borders of Ursa Major and been seen since 1978. the Institute of Astronomy, Canes Venatici, then tracks Cambridge for the use of southwards passing through Leo Looking ahead to 2004, the computing facilities. E&OE. in April and May. 2002 O7 highlight will almost certainly be

Lunar interference plot for the next six months, produced using GraphDark 2 by Richard Fleet.

BAA COMET SECTION NEWSLETTER