The Obiective View August 1998 Newsletter of the Northern Colorado Astronomical Society Thom Peck, President 962-9695 [email protected] Randy Moench, V Pres 493-7613 [email protected] Doug Moench Treasurer 221'-9455 [email protected] Tom Teters, Secretary 482-5702 [email protected] Randy Moenctu Web Site Editor WWW Page: http:/ /lamar.colostate.edu/-rmoench/ncasrdm.html David Chamness, A L correspondent 482-1794 Dan Laszlo, Newsletter Editor 498-9226 [email protected] Meetings first Thursday of each Month Next Meeting: August 6 7:30 pm Discovery Center Fort Collins " Establishing a Human Mission from Planet Earth: Technology Assessment and SocialForecasting of Moon/Mars Synergies " by CSU'sEligar Sadeh ** "* Club Businesswill precede the program, 7-7:30pm

August 6 NCAS Meeting Directions Irily 2 Program: Supernovas, by Dave Chamness Discovery Center, 703E ProspectRd, Fort Collins From Loveland go North on US 287 to ProspectRd in Fort The largest visible remnant of a catastrophic supernova Collins, go East about 0.5 miles. Look for the Discovery is the Gum Nebula, seen from the Southern Hemisphere Center sign on the South side of the street. in the constellation Vela. It extends over 60 degrees of From I-25, take Exit 268, head West into Fort Collins. sky and is 1300 light-years away. The brightest Continue past Lemay Ave about 0.5 miles and see the supernovas rival galaxies in brightness, with an absolute Discovery Center on the left. magnitude of 20. This is 10e10times the Sun's brightness, a million times brighter than Cepheid variables. NCAS Star Party, August 21or 22, Stove Prairie Site Supernovas are estimated to occur in the Milky Way From the Stove Prairie Schoolgo 1.1 mile west and bear Galaxy three times per century, but only 10% are visible west(right) after the fence for a tenth or two. Tom will to us. A supernova can release2.3 x 10e30megatons (or put out the star party sign on the left side of that road. 10e53ergs, 10e46joules, 7x10e45foot-pounds). A Type I You can call 482-5702if the weather is in doubt. The supernova lacks hydrogen lines in its spectrum. Sixty-six Stove Prairie School intersection is 13 miles west from percent of supernovas are Type Ia. They occur when a Bellvue and over the Rist Canyon Road, while in place carbon-oxygen white dwarf is greater than 1.44 solar this is a steep road, the county takes VERY good care of massesand explodes. The explosion is the consequenceof it. If you're coming from the Loveland area use the a collapse which triggers carbon fusiort which releases Masonville Road, the S.P.S. is 14 miles from the the energy to blow the star apart. This type is the Masonville intersection. The site itself is at about 7500ft, brightest and most uniform. Its light curve peaks and it has a good open horizon (5*-10*), but not cacti or decays sharply. Debris rushes out at 10000 km/sec. services. So bring warm clothes, several layers. Be White dwarf stars in binary systems can steal mass from prepared!!! This site is allowed us through the auspices their companion stars and accumulate enough to create a of the land manager/owner, he wanted us to CALL before Type Ia supernova. The Veil Nebula in Cygnus is a we went up there and asked that we leave the site clean remnant of a Type Ia supernova. Type Ib occurswhen a and in the same condition as we found it. Call Tom Teters Wolf-Rayet star, 30x the Sun's mass, has collapse of its with questions about the star party status, site or dates, iron core within 1 second. It shrinks from Earth size to 10- 482-5702, or Email [email protected]. 20 km across. The explosion is driven by a neutrino shock wave. Neutrinos from the center heat up matter falling NCAS Events,from Randy Moench, Vice President iry and it bouncesou! ejectedat 1O000km/second. There September3 Gravity Waves Bill Massman is decay of 56-Nickel to 56-Cobalt to 56-Iron. A pulsar Other FRASC Events remnant is created, composed of a superfluid superdense Longmont Astronomical SocietyMeetings sea of neutrons. The Eta Carinae Nebula is illimunated 7:30 pm, Third Thursday, monthly by a Wolf-Rayet star of 100 solar masses. In 1843 it Longmont Christian School, 550 N Coffman St ejected 2 to 3 solar masses. It is now trying to lose its hydrogen envelope, trying to build an iron core and blow August 20-23 Weekend Under the Stars up. A Type IIb supernova has hydrogen lines, and occurs Foxparlg Wyoming with iron core collapse in a red or blue supergiant. They Contact Marty CurrarL 307-635-5944,Cheyenne WY range from 8 to 100solar masses.They occur only in spiral Web info at http:/ /users.sisna.com/mcurran galaxies. They have a wide range of properties, and the absolutemagnitude is minus 14 to minus 20. Expansionis "Cosmic Chameleon:The Supernova in M81", Astronom, 2000 to 20000 km/second. They show calcium, sodium, February1994 irory titanium, and selenium lines in the spectrum. Supernova 1987a was a Type II. Its neutrinos reached "Ka-Boom: How Stars Explode", Astronomy, July 1997 Eafth 7 hours before the optical brightening was visible. It was 160000 light-years away, absolutemagnitude -14, apparent magnitude 4.3. This apparent magnitude was Rocky Mountain National Park Star Parties, Upper the brightest we have seen in 383 years. The Type II BeaverMeadows light curve shows a more gradual decline from peak than Dates remaining are: August 14, August 28. Let Ken Type I. A supernova1.2light-years away, with absolute Vanlew know if you would like to take part this summer, magnitude -20 would appear as bright as our Sun does to 226-2500extension 8724. us. With its 15,000K temperature,we would be bathed in UV and neutrinos. A supernova 600 light-years away would appear magnitude -8 to -13, and if 5 solar masses August Observers'Guide, by Brad Jarvis were ejected, 6 pounds of material would hit the Earttu 20,000 years later. The spectrum shows a little helium August is the month of the mighty Perseid meteor and much silicon. Hubble images of SN1987anow show a shower. Over 50 meteorsper hour would be expectedon a set of rings, likely traced by the pulsar remnant, or a moonless night as Earth sweeps up debris from Comet manifestation of its magnetic field. The Crab Nebula Swift-Tuttle. The meteors appear to come out of the pulsar is 6300 light years away; it has a magnetic field constellation Perseut which will be in the northeast just 10e12 times the Earth's. The nebula is 16 light-years below Cassiopeia. Unfortunately, a 68% illuminated across and expanding by 50 million miles a day. Moon will be closeby after 11pm on the 12th. Supernova discoveries numbered about 1-2 a year from 1900 to 1950. There were about 20 a year from 1950 to The best occultation of a star by an asteroid visible this 199Oand in1997,137 were found. From Jan-Mar1998,27 month will be on the 13th at 11:35p.m. MDT. For 15 have been detected. The Australian amateur, Rev. seconds,87 km wide 576 Emanuela will pass in front of Robert Evans, has visually found more than a dozen by the magnitude 10.3 star GSC 11741.528at RA 23h50m03s, memorizing galaxy photos and reporting the new objects DEC +11d24m47s.At this time, Emanuelawill be 1.566 he spots. Spiral galaxies can host all three types of au from the Earth in its 5.2 year orbit and 98% supernova, but elliptical galaxies have no current star illuminated (but it will still be dim: Magnitude 13.2). formation and can only show one type. Dave also Expect the star to dim by the difference in their discussed the peculiar effects of the extreme density of magnitudes(3.1). white dwarf stars, pulsars, and black holes. Escape velocity from the Earth is 11.2km/second, but {or a white This month we will be looking at the region of the sky dwarf it is 4900 km/second. A nickel dropped on a white around the constellation Cygnus, the Swan (also known as dwarf would trigger a 20,000kiloton explosiory like the the Northern Cross). This area is dominated by large effect of 1500 tons dropped on the Earth. Escapevelocity dust clouds and newly born stars in the Galaxy's Orion for a pulsar is 20O000km/second, and for a black hole is Arm (of which we are a part) as it spirals out toward us. over 300,000 km/sec, so no light can escape it. More At the Tail of the swan is the first magnitude information on supernovascan be found on the Internet at spectroscopic binary star Deneb (RA 20h41m26s,DEC www.spa-garching.mpg.de/ -ewald / sn11 / sn11.htm. +45d16m49s;mag 1.25, dist 990 pc), and at its head is a Dave's talk was timely, given the pair of supernovae favorite of amateur astronomers,the double star Albireo within reach of small telescopesthis spring. (RA 19h30m43s,DEC +27d57m35s;mag 3.1v,dist 118pc). Albireo, nearly lost in the luminosity of the Milky Way, Bio Note: Dave Chamness has been interested in consistsof an easily viewed yellow star and blue star. astronomy since grade school, and had a 2.4 inch refractor in ]unior High. He is an engineer at Hewlett Packard One of the most spectacular sights in the sky is the Veil working on integrated circuit manufacturing. Other Nebula (part of which is NGC 6960,at RA 20h46m, DEC interests include travel, photography, and forecasting +30d39m),also known as the Cygnus Loop. About770 pc the stock market. away, the Veil is part of the expanding shell of gas from a supernova,and appearsas a long wispy cloud. It is best Further Reading: seenin a very dark sky at low magnification.

"The Exploding Suns"by IsaacAsimov |ust to the west of Deneb is the North America Nebula, NGC 7000 (RA 20h58m, DEC +44d22m; dist - 700 pc). "Encyclopedia of Astronomy and Astrophysics" article This nebula, which appears like its namesake, is the "StellarStructure and Evolution", p 712-719. most visible part of a huge starbirth region.

"Breezes,Bangs, & Blowouts: Stellar Evolution Through Tustto the south of NGC 7000and Deneb is a dark cloud of Mass Loss,Part 1", Astronomy, September1985 dust which appearsas a rift in the Milky Way. 08/06/98 9:57:08 PM 3L4.0 0.7 Illuminoted Rise

Several planetary nebulae are worth looking at, in 08/06/98 LO:0L:44PM 22.7 25.4 Illuminoted Mox addition to the Ring and the Dumbbell. These include 08/06/98 tO:O2:?2 PM 44.4 24-L Into Shadow the Blinking Planetary, NGC 6826 (RA 19h44m48m,DEC 08/06/98 l-0:06:38 PM 99.2 O.3 In shodowSet +50d31m;mag 9.$ middle star mag 11;diam 25 arcsec); O8/O7/981A:29:32 PM 307.5 O.7 Illuminqted Rise (RA and the Blue Flash Nebula" NGC 6905,in Delphinus 08/07/98 1Q:33:27 PM 3L4.9 38.6 Into Shadow 20h22m24s,DEC +20d06m; mag 12.0, middle star mag 08/07/98 L0:34:.26PM 24.8 79.8 In shodowMox 13.9;diam 40 arcsec). By looking quickly at, away, and back at NGC 6826, you will see why this is called the 08/08/98 9:26:22 PM 372.6 0.8 Illuminqted Rise "Blinking" Planetary. 08,/08,/98 9:31:16 PM 35.2 33.2 Illuminoted Mox 08/08/98 9:32:33 PM 78.6 ?L.8 Into Shodow There are a multitude of globular clusters which can be 08/A8/98 9:35:52 PM 106.3 1.0 In shodowSet viewed here. Among them are M56 (RA 19h16m36s,DEC +30d11m;mag 8.3, dist 9.8 kpc), M71 (RA 19h53m48s, 08/09/98 9:58:41 PM 304.6 0.4 Itluminoted Rise DEC +18d47m; mag 8.O dist 4.4 kpc), and M15 (RA 08,/09,/9810:03:35 PM 231-.7 65.9 lnto Shodow 08/09/98 10:08:30 PM 134.5 O.9 In shodowSet 21h30m00s,DEC +12d10m;mag 6.O dist 9.7kpc). 08/t0/98 8:55:21 PM 310.4 0.1 Illuminoted Rise Finally, we can look at an interesting asterism (star 08110,/98 9:00:16 PM 23.1 46.1 Illuminoted Max pattern): the Coat Hanger, Collinder (Cr) 399, in 08/tO/98 9:02:43 PNI 104.5 15.0 Into Shqdow Vulpecula (RA 19h25m,DEC +20d05m). The starsin the Coat Hanger are not physically associatedwith 08/tt/98 9127:54 PM 301.3 0.5 Itluminoted Rise eachother,varying from 67 to 276 pc away. A8/11/CR 9:32:48 PM ??1.7 41.R Tl I rrminoted Max 08/IL/98 9:33:47 PM I75.t 30.2 Into Shodow The map overleafis for August L5 at 10:00p.m. A8/B/98 8:57:.@2PM 297.6 0.3 Illuminoted Rise Mox BestLooks O8/L3/98 9:01":56PM 221.2 27.4 Illuminoted 08/L3/98 9:04:23 PM 165.1 lO.7 Into Shodow N4oon Near Antar es BI 2, near Aldebaran 8 I 76 Near Mars and Venus 8/1,8-20 09/0I/98 5:38:11 AM ?02.6 6.6 Out of Shodow Mercury Near Venus in Nn 8I 27 to 9I 15 09/01/98 5:4L:21 AM 139.6 28.9 Illuminqted Mqx Venus Brilliantin E, mornings. Near Mars8l1.-7 09/OL/98 5:46:15 AM 61.8 0.2 Illuminoted Set Mars InM44am8/31 and9l1. jupiter In S late at night A Few lridium Satellite Flares. Saturn InS, morning The intensity of these flares is very sensitive to your Uranus, Neptune In S midnight positiory so please try to know your coordinates as Pluto Magnitude 13.7,in S evenings accurately as possible. A position error of 10km on the ground can change the flare intensity by several visual Perseid meteors peak Aug 11-13. Moon will interfere magnitudes. Accurate time is also critical. Observer's startingabout L0:30pm L1ttr,after L1 pm on 12th. Location: Near Lemay and Trilby in Fort Collins CO ( 40.50'N 105.05"W). Local Time: Mountain Daylight Mir in August. Times are estimatesas of late |uly. Best Time (GMT - 6:00) passesare underlined. Current Mir and Iridium predictions are available on the Web at: Times are MDT, Fort Collins/Loveland. Az is compass http:/ I www2.gsoc.dlr.de/scripts/ satvis/ satvis.asp? directiory N:0, E:90, 5:180, W:270. Elevation above Lat:40.58&Lng:-105.0500&Loc:Fort+Collins&TZ:MDT horizory 10 degrees,about a hand-width at arm's length. Site now gives directions for maximum Iridium flare magnitude. Mir Complex Time MDT Az El Sotell ite Date Time Magnitude Elev. Azimuth MM/DD/YYHH:MM:SS Deg Deg Visibility O4 Aug 04:16:05 -3 L2' 91'(E) 04 Aug A5:06:25 -4 t4" 26'(NE) 08/04/98 LO:77:4LPl'l 314.1 O.O Itluminoted Rise 05 Aug @4:@9:52 -4 1L' 93'(E) A8/O4/98 1Q:32:26 PM 22.7 ZO.3 Into Shodow O6 Aug 2L:38:07 -4 13' 350'(N) 08/44/98 10:32:35 PM 27.7 20.2 In shodowMax 09 Aug @3:54:06 -4 L2" 101'(E) 08/04/98 LO:37:1L Pl'l 92.O O.t In shodowSet IO Aug 03:47:53 -3 t2" 103'(E)

08/05/98 LL:00:O9 Pl"l 309.8 0.2 Illuminoted Rise 08/05/98 LL:@3:?LPl"l 322.3 ?0.5 Into Shodow 08/05/98 L1:O5:O4PM ??.2 52.3 In shodowMox 08/05/98 11:@9:58PM 7L7.2 7.1 In shqdowSet Map for September 15 at 9:00PM MDT

From: c/o Dan Laszlo 2001S Shields St Building H Fort Collins CO 80526

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