DOCSLIB.ORG

38 Minor Planet Bulletin 43

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
38 Minor Planet Bulletin 43 38 less favorable apparitions at intervals of 2.056 years (e.g., 2017 POLE AND SHAPE FOR THE NEA (436724) 2011 UW158 Sep with V ~ 20.7) will provide opportunities for additional observations with large telescope apertures for elucidating the Albino Carbognani nature of fast-spinning, rocky asteroids. Astronomical Observatory of the Aosta Valley Autonomous Region (OAVdA) Acknowledgements Lignan 39, 11020 Nus (Aosta), ITALY [email protected] Asteroid ephemeris information was provided by Caltech’s Jet Propulsion Laboratory web site: http://ssd.jpl.nasa.gov/horizons. Bruce L. Gary Calibration with SDSS magnitudes in the UCAC4 catalog was Hereford Arizona Observatory made possible through the use of the AAVSO Photometric All-Sky Hereford, Arizona, USA Survey (APASS), funded by the Robert Martin Ayers Sciences Fund. I want to record my appreciation to Dr. Arne Henden for Julian Oey initiating the APASS project; this is a sentiment I feel every Blue Mountains Observatory morning after a night’s observations as I select APASS stars for Leura, AUSTRALIA calibration. Radar images were kindly provided by the Arecibo Observatory, which is operated by SRI International under a Giorgio Baj cooperative agreement with the National Science Foundation Astronomical Station of Monteviasco (AST-1100968), and in alliance with Ana G. Méndez-Universidad Varese, ITALY Metropolitana, and the Universities Space Research Association. The Arecibo planetary radar program is supported by the National Paolo Bacci Aeronautics and Space Administration under Grant Nos. Astronomical Observatory of San Marcello Pistoiese NNX12AF24G and NNX13AQ46G issued through the Near-Earth Pistoia, ITALY Object Observations program. The “spin frequency/diameter” (Received: 2015 Oct 7) diagram (Fig. 8) is a modification of a graph at the IAU Minor Planet Center web site, which is based on data from the asteroid lightcurve database (Warner et al., 2009). The near-Earth asteroid (436724) 2011 UW158 was followed by an international team of observers on 31 References nights between 2015 Jun 17 and Sep 26. By using the standard lightcurve inversion method with the combined Belskaya, I.N., Shevchenko, V.B. (2000). “Opposition Effect of photometry data set, we obtained a unique spin axis Asteroids.” Icarus, 147, 94-105. solution with ecliptic coordinates . = 290° ± 3°, Gary, B.L. (2014). Exoplanet Observing for Amateurs, Hereford, 4 = –39° ± 2°, a sidereal period PS = 0.610752 ± AZ: Reductionist Publications. 0.000001 h, and a shape model qualitatively consistent with radar observations. Gary, B.L. (2015a). http://brucegary.net/asteroids/ Gary, B.L. (2015b). http://www.brucegary.net/UW158/ Asteroids of size D " 0.15 km generally do not have periods P # 2.2 h, a limit known as the cohesionless spin-barrier. This Gary, B.L. (2015c). http://brucegary.net/SA/ barrier can be explained by the rubble-pile structure model. According to this model, the asteroids are made up of collisional Gary, B.L. (2015d). http://www.brucegary.net/UW158/#Moon breakup fragments bound together only by mutual gravitational force (Pravec and Harris 2000). The exceptions to this “rule,” Gary, B.L. (2015e). http://www.brucegary.net/mags/#Examples called large super-fast rotators (LSFR), are very few; 2001 OE84, (335433) 2005 UW163, and 2011 XA3 are the best known Hapke, B., Denevi. B., Sato, H., Braden, S., Robson, M. (2015). examples. The presence of these objects was theorized for the first http://onlinelibrary.wiley.com/doi/10.1029/2011JE003916/full time by Holsapple (2007). His analysis shows that the cohesion necessary to bind together a rubble-pile asteroid under the spin- Pravec, P., Kusnirak, P., Sarounova, L., Harris, A.W., Binzel, R. barrier value is low, but he does not specifically propose a theory P., Rivkin, A.S. (2002). “Large Coherent Asteroid 2001 OE84”, for how cohesion could arise. These results have been confirmed Proc. Asteroids, Comets, Meteors (ACM 2002), Jul 29 – Aug 02, and enriched by subsequent theoretical studies, such as by Sànchez Tech. Univ. Berlin, Berlin, Germany (ESA SP-500). and Scheeres (2014), in which a model for the origin of the Shevchenko, V.G, (1996). “Analysis of the Asteroid Phase cohesion forces within a regolith has been proposed. The presence Dependencies of Brightness.” Lunar Planet Sci. 27, 1193. of cohesion forces begins to be important only for objects with diameter D < 10 km. So, for small bodies (0.15 km < D <10 km) Shevchenko, V.G. (1997). “Analysis of Asteroid Brightness-Phase with rubble-pile structure, the presence of even a very small Relations.” Solar System Res. 31, 219-234. amount of strength allows much more rapid spin than the simple cohesionless spin-barrier value. Warner, B.D., Harris, A.W., Pravec, P. (2009). “The Asteroid Lightcurve Database.” Icarus 202, 134-146. Updated 2015 Sept. The asteroid 2011 UW158 is a near-Earth asteroid and potentially http://www.minorplanet.info/lightcurvedatabase.html hazardous object. It was discovered on 2011 Oct 25 by the Pan- STARRS observatory at Haleakala (Hawaii, USA). A flyby with the Earth occurred on 2015 Jul 19 at a distance of 0.0164 AU, so this object also became a radar target for Goldstone and Arecibo. This asteroid, with a synodic period of about 37 minutes and an Minor Planet Bulletin 43 (2016) 39 absolute magnitude of about 19.5 (D = 240-740 m) is an example using MPO LCInvert v11.1.0.2 (Bdw Publishing), which of LSFR. This short period was first found by Bruce Gary on 2015 implements the core algorithms developed by Kaasalainen and Jun 17 (see his paper elsewhere in this issue) and independently by then converted to C language by Josef Durech. Julian Oey on Jul 1. Table I shows the instruments used while Table II lists the observing sessions that produced lightcurves used for this analysis. The photometric coverage was dense because our purpose was to determine the pole of rotation and convex shape using the standard lightcurve (LC) inversion method (Kaasalainen et al. 2001; Kaasalainen and Torppa, 2001). In most cases, it is not possible to get a reasonable solution for a pole using LC inversion with photometric observations from one apparition. It may be possible to get an initial solution if, as in the case of ours observations, the total span covers several rotations and a large range of phase angles, the synodic period is well- established, and the photometric data are of good quality. It is also Figure 1. Distribution of phase angle bisector (PAB) for 2011 helpful if the viewing aspect, as measured by the phase angle UW158. Data is from Table 2. bisector, goes through a relatively large range as well. In our case the range of observed phase angle is 62° to 109° and 109° to 20°; Period Search the amplitudes of angle bisector are LPAB = 137° and BPAB = 64° (Fig. 1). The inversion process started by finding the sidereal rotation period of the asteroid. A search in MPO LCInvert was confined to Observer Telescope CCD camera 0.6100 to 0.6115 h, a range that includes the synodic period found Bacci Ref. 0.60-m f/4 Apogee Alta 1024 in the single phased LC, with weight 0.5. However, inclusion of all Baj RC 0.25-m f/8 SBIG-ST10 observations listed in Table II leads to %2 values that are quite high. Carbognani RC 0.81-m f/7.9 FLI 1001E Gary SC 0.35-m f/10 SBIG-ST10XME After some tests, we found that by restricting observations to those Oey CDK 0.61-m f/6.8 Apogee U42 by Gary (in this way the range of the phase angle remains unchanged) and those before Aug 15 for the other observers, the %2 Table 1. Observers, telescopes and CCD camera used. values were reduced to reasonable values. Obs. yyyy/mm/dd Phase LPAB BPAB A (°) (°) (°) (mag) The search process found an isolated, deep, and flat minimum in Gary 2015/06/17 62.3 230.7 -12.9 0.50 the plot of %2 vs. sidereal period (Fig. 2). A renormalization was Gary 2015/06/20 65.7 231.9 -12.5 0.52 2 2 Oey 2015/07/01 79.0 236.4 -9.3 0.67 not necessary since reduced % ~ 1.0 (i.e., N = 24 and sum % is Oey 2015/07/02 80.3 236.8 -9.3 0.67 also ~24). The minimum appears asymmetrical, i.e. the descending Oey 2015/07/03 81.6 237.1 -8.8 0.73 branch is less steep than the ascending branch. For this reason we Oey 2015/07/06 85.8 238.1 -6.7 0.76 assumed the value of the point to the right, Oey 2015/07/08 88.9 238.6 -4.7 0.71 0.6107643 h, for the starting period in the pole search. Gary 2015/07/08 88.9 238.6 -4.7 0.70 Gary 2015/07/12 96.0 239.4 2.3 0.70 Gary 2015/07/20 109.3 269.9 50.6 0.92 Baj 2015/07/23 101.9 314.6 50.5 1.92 Bacci 2015/08/01 82.0 341.4 30.0 2.38 Carb. 2015/08/02 80.4 342.4 29.0 1.96 Gary 2015/08/03 78.9 343.3 28.1 1.95 Gary 2015/08/04 77.5 344.1 27.3 2.05 Carb. 2015/08/11 68.3 348.9 23.4 1.96 Gary 2015/08/13 65.8 350.1 22.6 1.84 Bacci 2015/08/14 64.6 350.7 22.3 1.82 Carb. 2015/08/19 58.6 353.4 20.8 1.62 Bacci 2015/08/20 57.4 353.9 20.5 1.65 Gary 2015/08/29 47.0 357.9 18.6 1.46 Baj 2015/09/05 39.1 0.5 17.3 1.27 Figure 2.
Load more

Recommended publications
  • SPECIAL Comet Shoemaker-Levy 9 Collides with Jupiter
    SL-9/JUPITER ENCOUNTER - SPECIAL Comet Shoemaker-Levy 9 Collides with Jupiter THE CONTINUATION OF A UNIQUE EXPERIENCE R.M. WEST, ESO-Garching After the Storm Six Hectic Days in July eration during the first nights and, as in other places, an extremely rich data The recent demise of comet Shoe­ ESO was but one of many profes­ material was secured. It quickly became maker-Levy 9, for simplicity often re­ sional observatories where observations evident that infrared observations, es­ ferred to as "SL-9", was indeed spectac­ had been planned long before the critical pecially imaging with the far-IR instru­ ular. The dramatic collision of its many period of the "SL-9" event, July 16-22, ment TIMMI at the 3.6-metre telescope, fragments with the giant planet Jupiter 1994. It is now clear that practically all were perfectly feasible also during day­ during six hectic days in July 1994 will major observatories in the world were in­ time, and in the end more than 120,000 pass into the annals of astronomy as volved in some way, via their telescopes, images were obtained with this facility. one of the most incredible events ever their scientists or both. The only excep­ The programmes at most of the other predicted and witnessed by members of tions may have been a few observing La Silla telescopes were also successful, this profession. And never before has a sites at the northernmost latitudes where and many more Gigabytes of data were remote astronomical event been so ac­ the bright summer nights and the very recorded with them.
    [Show full text]
  • KAREN J. MEECH February 7, 2019 Astronomer
    BIOGRAPHICAL SKETCH – KAREN J. MEECH February 7, 2019 Astronomer Institute for Astronomy Tel: 1-808-956-6828 2680 Woodlawn Drive Fax: 1-808-956-4532 Honolulu, HI 96822-1839 [email protected] PROFESSIONAL PREPARATION Rice University Space Physics B.A. 1981 Massachusetts Institute of Tech. Planetary Astronomy Ph.D. 1987 APPOINTMENTS 2018 – present Graduate Chair 2000 – present Astronomer, Institute for Astronomy, University of Hawaii 1992-2000 Associate Astronomer, Institute for Astronomy, University of Hawaii 1987-1992 Assistant Astronomer, Institute for Astronomy, University of Hawaii 1982-1987 Graduate Research & Teaching Assistant, Massachusetts Inst. Tech. 1981-1982 Research Specialist, AAVSO and Massachusetts Institute of Technology AWARDS 2018 ARCs Scientist of the Year 2015 University of Hawai’i Regent’s Medal for Research Excellence 2013 Director’s Research Excellence Award 2011 NASA Group Achievement Award for the EPOXI Project Team 2011 NASA Group Achievement Award for EPOXI & Stardust-NExT Missions 2009 William Tylor Olcott Distinguished Service Award of the American Association of Variable Star Observers 2006-8 National Academy of Science/Kavli Foundation Fellow 2005 NASA Group Achievement Award for the Stardust Flight Team 1996 Asteroid 4367 named Meech 1994 American Astronomical Society / DPS Harold C. Urey Prize 1988 Annie Jump Cannon Award 1981 Heaps Physics Prize RESEARCH FIELD AND ACTIVITIES • Developed a Discovery mission concept to explore the origin of Earth’s water. • Co-Investigator on the Deep Impact, Stardust-NeXT and EPOXI missions, leading the Earth-based observing campaigns for all three. • Leads the UH Astrobiology Research interdisciplinary program, overseeing ~30 postdocs and coordinating the research with ~20 local faculty and international partners.
    [Show full text]
  • Early Observations of the Interstellar Comet 2I/Borisov
    geosciences Article Early Observations of the Interstellar Comet 2I/Borisov Chien-Hsiu Lee NSF’s National Optical-Infrared Astronomy Research Laboratory, Tucson, AZ 85719, USA; [email protected]; Tel.: +1-520-318-8368 Received: 26 November 2019; Accepted: 11 December 2019; Published: 17 December 2019 Abstract: 2I/Borisov is the second ever interstellar object (ISO). It is very different from the first ISO ’Oumuamua by showing cometary activities, and hence provides a unique opportunity to study comets that are formed around other stars. Here we present early imaging and spectroscopic follow-ups to study its properties, which reveal an (up to) 5.9 km comet with an extended coma and a short tail. Our spectroscopic data do not reveal any emission lines between 4000–9000 Angstrom; nevertheless, we are able to put an upper limit on the flux of the C2 emission line, suggesting modest cometary activities at early epochs. These properties are similar to comets in the solar system, and suggest that 2I/Borisov—while from another star—is not too different from its solar siblings. Keywords: comets: general; comets: individual (2I/Borisov); solar system: formation 1. Introduction 2I/Borisov was first seen by Gennady Borisov on 30 August 2019. As more observations were conducted in the next few days, there was growing evidence that this might be an interstellar object (ISO), especially its large orbital eccentricity. However, the first astrometric measurements do not have enough timespan and are not of same quality, hence the high eccentricity is yet to be confirmed. This had all changed by 11 September; where more than 100 astrometric measurements over 12 days, Ref [1] pinned down the orbit elements of 2I/Borisov, with an eccentricity of 3.15 ± 0.13, hence confirming the interstellar nature.
    [Show full text]
  • Comet Section Observing Guide
    Comet Section Observing Guide 1 The British Astronomical Association Comet Section www.britastro.org/comet BAA Comet Section Observing Guide Front cover image: C/1995 O1 (Hale-Bopp) by Geoffrey Johnstone on 1997 April 10. Back cover image: C/2011 W3 (Lovejoy) by Lester Barnes on 2011 December 23. © The British Astronomical Association 2018 2018 December (rev 4) 2 CONTENTS 1 Foreword .................................................................................................................................. 6 2 An introduction to comets ......................................................................................................... 7 2.1 Anatomy and origins ............................................................................................................................ 7 2.2 Naming .............................................................................................................................................. 12 2.3 Comet orbits ...................................................................................................................................... 13 2.4 Orbit evolution .................................................................................................................................... 15 2.5 Magnitudes ........................................................................................................................................ 18 3 Basic visual observation ........................................................................................................
    [Show full text]
  • The Comet's Tale
    THE COMET’S TALE Newsletter of the Comet Section of the British Astronomical Association Volume 5, No 1 (Issue 9), 1998 May A May Day in February! Comet Section Meeting, Institute of Astronomy, Cambridge, 1998 February 14 The day started early for me, or attention and there were displays to correct Guide Star magnitudes perhaps I should say the previous of the latest comet light curves in the same field. If you haven’t day finished late as I was up till and photographs of comet Hale- got access to this catalogue then nearly 3am. This wasn’t because Bopp taken by Michael Hendrie you can always give a field sketch the sky was clear or a Valentine’s and Glynn Marsh. showing the stars you have used Ball, but because I’d been reffing in the magnitude estimate and I an ice hockey match at The formal session started after will make the reduction. From Peterborough! Despite this I was lunch, and I opened the talks with these magnitude estimates I can at the IOA to welcome the first some comments on visual build up a light curve which arrivals and to get things set up observation. Detailed instructions shows the variation in activity for the day, which was more are given in the Section guide, so between different comets. Hale- reminiscent of May than here I concentrated on what is Bopp has demonstrated that February. The University now done with the observations and comets can stray up to a offers an undergraduate why it is important to be accurate magnitude from the mean curve, astronomy course and lectures are and objective when making them.
    [Show full text]
  • Interstellar Comet 2I/Borisov
    Interstellar comet 2I/Borisov Piotr Guzik1*, Michał Drahus1*, Krzysztof Rusek2, Wacław Waniak1, Giacomo Cannizzaro3,4, Inés Pastor-Marazuela5,6 1 Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Kraków, Poland 2 AGH University of Science and Technology, al. Mickiewicza 30, Kraków 30-059, Poland 3 SRON, Netherlands Institute for Space Research, Sorbonnelaan, 2, NL-3584CA Utrecht, the Netherlands 4 Department of Astrophysics/IMAPP, Radboud University, P.O. Box 9010, 6500 GL Nijmegen, the Netherlands 5 Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands 6 ASTRON, Netherlands Institute for Radio Astronomy, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands * These authors contributed equally to this work. Interstellar comets penetrating through the Solar System were anticipated for decades1,2. The discovery of non-cometary 1I/‘Oumuamua by Pan-STARRS was therefore a huge surprise and puzzle. Furthermore, its physical properties turned out to be impossible to reconcile with Solar System objects3-5, which radically changed our view on interstellar minor bodies. Here, we report the identification of a new interstellar object which has an evidently cometary appearance. The body was identified by our data mining code in publicly available astrometric data. The data clearly show significant systematic deviation from what is expected for a parabolic orbit and are consistent with an enormous orbital eccentricity of 3.14 ± 0.14. Images taken by the William Herschel Telescope and Gemini North telescope show an extended coma and a faint, broad tail – the canonical signatures of cometary activity. The observed g’ and r’ magnitudes are equal to 19.32 ± 0.02 and 18.69 ± 0.02, respectively, implying g’-r’ color index of 0.63 ± 0.03, essentially the same as measured for the native Solar System comets.
    [Show full text]
  • Initial Characterization of Interstellar Comet 2I/Borisov
    Initial characterization of interstellar comet 2I/Borisov Piotr Guzik1*, Michał Drahus1*, Krzysztof Rusek2, Wacław Waniak1, Giacomo Cannizzaro3,4, Inés Pastor-Marazuela5,6 1 Astronomical Observatory, Jagiellonian University, Kraków, Poland 2 AGH University of Science and Technology, Kraków, Poland 3 SRON, Netherlands Institute for Space Research, Utrecht, the Netherlands 4 Department of Astrophysics/IMAPP, Radboud University, Nijmegen, the Netherlands 5 Anton Pannekoek Institute for Astronomy, University of Amsterdam, Amsterdam, the Netherlands 6 ASTRON, Netherlands Institute for Radio Astronomy, Dwingeloo, the Netherlands * These authors contributed equally to this work; email: [email protected], [email protected] Interstellar comets penetrating through the Solar System had been anticipated for decades1,2. The discovery of asteroidal-looking ‘Oumuamua3,4 was thus a huge surprise and a puzzle. Furthermore, the physical properties of the ‘first scout’ turned out to be impossible to reconcile with Solar System objects4–6, challenging our view of interstellar minor bodies7,8. Here, we report the identification and early characterization of a new interstellar object, which has an evidently cometary appearance. The body was discovered by Gennady Borisov on 30 August 2019 UT and subsequently identified as hyperbolic by our data mining code in publicly available astrometric data. The initial orbital solution implies a very high hyperbolic excess speed of ~32 km s−1, consistent with ‘Oumuamua9 and theoretical predictions2,7. Images taken on 10 and 13 September 2019 UT with the William Herschel Telescope and Gemini North Telescope show an extended coma and a faint, broad tail. We measure a slightly reddish colour with a g′–r′ colour index of 0.66 ± 0.01 mag, compatible with Solar System comets.
    [Show full text]
  • Carbon Monoxide in Jupiter After Comet Shoemaker-Levy 9
    ICARUS 126, 324±335 (1997) ARTICLE NO. IS965655 Carbon Monoxide in Jupiter after Comet Shoemaker±Levy 9 1 1 KEITH S. NOLL AND DIANE GILMORE Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, Maryland 21218 E-mail: [email protected] 1 ROGER F. KNACKE AND MARIA WOMACK Pennsylvania State University, Erie, Pennsylvania 16563 1 CAITLIN A. GRIFFITH Northern Arizona University, Flagstaff, Arizona 86011 AND 1 GLENN ORTON Jet Propulsion Laboratory, Pasadena, California 91109 Received February 5, 1996; revised November 5, 1996 for roughly half the mass. In high-temperature shocks, Observations of the carbon monoxide fundamental vibra- most of the O is converted to CO (Zahnle and MacLow tion±rotation band near 4.7 mm before and after the impacts 1995), making CO one of the more abundant products of of the fragments of Comet Shoemaker±Levy 9 showed no de- a large impact. tectable changes in the R5 and R7 lines, with one possible By contrast, oxygen is a rare element in Jupiter's upper exception. Observations of the G-impact site 21 hr after impact atmosphere. The principal reservoir of oxygen in Jupiter's do not show CO emission, indicating that the heated portions atmosphere is water. The Galileo Probe Mass Spectrome- of the stratosphere had cooled by that time. The large abun- ter found a mixing ratio of H OtoH of X(H O) # 3.7 3 dances of CO detected at the millibar pressure level by millime- 2 2 2 24 P et al. ter wave observations did not extend deeper in Jupiter's atmo- 10 at P 11 bars (Niemann 1996).
    [Show full text]
  • The Physical Characterization of the Potentially-‐Hazardous
    The Physical Characterization of the Potentially-Hazardous Asteroid 2004 BL86: A Fragment of a Differentiated Asteroid Vishnu Reddy1 Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719, USA Email: [email protected] Bruce L. Gary Hereford Arizona Observatory, Hereford, AZ 85615, USA Juan A. Sanchez1 Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719, USA Driss Takir1 Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719, USA Cristina A. Thomas1 NASA Goddard Spaceflight Center, Greenbelt, MD 20771, USA Paul S. Hardersen1 Department of Space Studies, University of North Dakota, Grand Forks, ND 58202, USA Yenal Ogmen Green Island Observatory, Geçitkale, Mağusa, via Mersin 10 Turkey, North Cyprus Paul Benni Acton Sky Portal, 3 Concetta Circle, Acton, MA 01720, USA Thomas G. Kaye Raemor Vista Observatory, Sierra Vista, AZ 85650 Joao Gregorio Atalaia Group, Crow Observatory (Portalegre) Travessa da Cidreira, 2 rc D, 2645- 039 Alcabideche, Portugal Joe Garlitz 1155 Hartford St., Elgin, OR 97827, USA David Polishook1 Weizmann Institute of Science, Herzl Street 234, Rehovot, 7610001, Israel Lucille Le Corre1 Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719, USA Andreas Nathues Max-Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany 1Visiting Astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under Cooperative Agreement no. NNX-08AE38A with the National Aeronautics and Space Administration, Science Mission Directorate, Planetary Astronomy Program. Pages: 27 Figures: 8 Tables: 4 Proposed Running Head: 2004 BL86: Fragment of Vesta Editorial correspondence to: Vishnu Reddy Planetary Science Institute 1700 East Fort Lowell Road, Suite 106 Tucson 85719 (808) 342-8932 (voice) [email protected] Abstract The physical characterization of potentially hazardous asteroids (PHAs) is important for impact hazard assessment and evaluating mitigation options.
    [Show full text]
  • Detection of Exocometary CO Within the 440 Myr Old Fomalhaut Belt: a Similar CO+CO2 Ice Abundance in Exocomets and Solar System Comets
    UCLA UCLA Previously Published Works Title Detection of Exocometary CO within the 440 Myr Old Fomalhaut Belt: A Similar CO+CO2 Ice Abundance in Exocomets and Solar System Comets Permalink https://escholarship.org/uc/item/1zf7t4qn Journal Astrophysical Journal, 842(1) ISSN 0004-637X Authors Matra, L MacGregor, MA Kalas, P et al. Publication Date 2017-06-10 DOI 10.3847/1538-4357/aa71b4 Peer reviewed eScholarship.org Powered by the California Digital Library University of California The Astrophysical Journal, 842:9 (15pp), 2017 June 10 https://doi.org/10.3847/1538-4357/aa71b4 © 2017. The American Astronomical Society. All rights reserved. Detection of Exocometary CO within the 440 Myr Old Fomalhaut Belt: A Similar CO+CO2 Ice Abundance in Exocomets and Solar System Comets L. Matrà1, M. A. MacGregor2, P. Kalas3,4, M. C. Wyatt1, G. M. Kennedy1, D. J. Wilner2, G. Duchene3,5, A. M. Hughes6, M. Pan7, A. Shannon1,8,9, M. Clampin10, M. P. Fitzgerald11, J. R. Graham3, W. S. Holland12, O. Panić13, and K. Y. L. Su14 1 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK; [email protected] 2 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 3 Astronomy Department, University of California, Berkeley CA 94720-3411, USA 4 SETI Institute, Mountain View, CA 94043, USA 5 Univ. Grenoble Alpes/CNRS, IPAG, F-38000 Grenoble, France 6 Department of Astronomy, Van Vleck Observatory, Wesleyan University, 96 Foss Hill Dr., Middletown, CT 06459, USA 7 MIT Department of Earth, Atmospheric, and
    [Show full text]
  • Guide User Manual (PDF)
    CONTENTS 1: 2 Installing Guide 2: 2 Getting Help 3: 3 What Guide is showing you 4: 4 Panning and zooming 5: 5 Finding objects 5a: 8 Finding stars 5b: 10 Finding galaxies 5c: 12 Finding nebulae 5d: 12 Entering coordinates 6: 13 Getting information about objects 6a: 15 Measuring angular distances on the screen 6b: 15 Quick info 7: 16 The Display menu 7a: 17 The Star Display menu 7b: 19 The Data Shown menu 7c: 21 Planet display 7d: 23 The Camera Frame menu 7e: 24 The Legend Menu 7f: 26 Measurement markings (grids, ticks, etc.) 7g: 28 Backgrounds dialog 8: 29 Changing settings 8a: 34 Location dialog 8b: 35 Inversion dialog 9: 36 Overlays menu 10: 38 User Object menu 11: 39 Telescope control 12: 42 DOS Printer setup and printing 13: 43 PostScript charts 14: 44 The time dialog 15: 46 Planetary animation and ephemeris generation 16: 50 Tables menu 17: 52 Extras menu 17a: 54 DSS/RealSky Images 17b: 56 Downloading star data from the Internet 17c: 58 Installing to the hard drive 17d: 59 Asteroid options 18: 62 Eclipses, occultations, transits 19: 63 Saving and going to marks 20: 64 User-added (.TDF) datasets 21: 65 Adding your own notes for objects 22: 66 About Guide's data 23: 67 Accessing Guide's data from your own programs 24: 68 Acknowledgments Appendices: A: 70 RA and Declination Explained B: 70 Precession and Epochs Explained C: 71 Altitude and Azimuth (Alt/Az) Explained D: 72 Troubleshooting Positions 1 E: 73 Notes on Accuracy F: 73 Adding New Comets G: 75 Astronomical Magnitudes H: 75 Copyright and Liability Notices I: 77 List of Program-Wide Hotkeys Index 79 Questions and bug reports should be sent to: Project Pluto 168 Ridge Road Bowdoinham ME 04008 Fax (207) 666 3149 Tel (207) 666 5750 Tel (800) 777 5886 E-mail: [email protected] WWW: http://www.projectpluto.com 1: HOW TO INSTALL GUIDE To install Guide, put the Guide DVD into the DVD drive.
    [Show full text]
  • Physical Characterization of NEA Large Super-Fast Rotator (436724) 2011 UW158
    EPJ manuscript No. (will be inserted by the editor) Physical characterization of NEA Large Super-Fast Rotator (436724) 2011 UW158 A. Carbognani1, B. L. Gary2, J. Oey3, G. Baj4, and P. Bacci5 1 Astronomical Observatory of the Autonomous Region of Aosta Valley (OAVdA), Aosta - Italy 2 Hereford Arizona Observatory (Hereford, Cochise - U.S.A.) 3 Blue Mountains Observatory (Leura, Sydney - Australia) 4 Astronomical Station of Monteviasco (Monteviasco, Varese - Italy) 5 Astronomical Observatory of San Marcello Pistoiese (San Marcello Pistoiese, Pistoia - Italy) Received: date / Revised version: date Abstract. Asteroids of size larger than 0.15 km generally do not have periods smaller than 2.2 hours, a limit known as cohesionless spin-barrier. This barrier can be explained by the cohesionless rubble-pile structure model. There are few exceptions to this “rule”, called LSFRs (Large Super-Fast Rotators), as (455213) 2001 OE84, (335433) 2005 UW163 and 2011 XA3. The near-Earth asteroid (436724) 2011 UW158 was followed by an international team of optical and radar observers in 2015 during the flyby with Earth. It was discovered that this NEA is a new candidate LSFR. With the collected lightcurves from optical observations we are able to obtain the amplitude-phase relationship, sideral rotation period (PS = 0.610752 ± 0.000001 ◦ ◦ ◦ ◦ h), a unique spin axis solution with ecliptic coordinates λ = 290 ± 3 , β = 39 ± 2 and the asteroid 3D model. This model is in qualitative agreement with the results from radar observations. PACS. PACS-key discribing text of that key – PACS-key discribing text of that key 1 Introduction The near-Earth asteroid (436724) 2011 UW158 was discovered on 2011 Oct 25 by the Pan-STARRS 1 Observatory at Haleakala (Hawaii, USA).
    [Show full text]