| 词条 | 5642 Bobbywilliams |
| 释义 |
| minorplanet = yes | name = 5642 Bobbywilliams | background = #FA8072 | image = | image_size = | caption = | discovery_ref = | discovered = 27 July 1990 | discoverer = H. E. Holt | discovery_site = Palomar Obs. | mpc_name = (5642) Bobbywilliams | alt_names = {{mp|1990 OK|1}} | named_after = Bobby G. Williams {{small|(JPL engineer)}}[2] | mp_category = Mars-crosser [4][5] | orbit_ref = | epoch = 4 September 2017 (JD 2458000.5) | uncertainty = 0 | observation_arc = 41.97 yr (15,330 days) | aphelion = 3.0867 AU | perihelion = 1.5454 AU | semimajor = 2.3161 AU | eccentricity = 0.3327 | period = 3.52 yr (1,287 days) | mean_anomaly = 235.13° | mean_motion = {{Deg2DMS|0.2796|sup=ms}} / day | inclination = 24.956° | asc_node = 310.12° | arg_peri = 39.038° | dimensions = 4.71 km {{small|(calculated)}}[5] | rotation = {{val|4.8341|0.0003}} h[8] | albedo = 0.20 {{small|(assumed)}}[5] | spectral_type = S [5] | abs_magnitude = 14.0[5]{{·}}{{val|14.24|0.23}}[13] }} 5642 Bobbywilliams, provisional designation {{mp|1990 OK|1}}, is an eccentric, stony asteroid and Mars-crosser from the inner regions of the asteroid belt, approximately 4.7 kilometers in diameter. It was discovered on 27 July 1990, by American astronomer Henry E. Holt at Palomar Observatory in California, United States.[4] The asteroid was named for JPL engineer Bobby Williams.[2] Orbit and classificationBobbywilliams orbits the Sun in the inner main-belt at a distance of 1.5–3.1 AU once every 3 years and 6 months (1,287 days). Its orbit has an eccentricity of 0.33 and an inclination of 25° with respect to the ecliptic. A first precovery was taken at the Australian Siding Spring Observatory in 1975, extending the body's observation arc by 15 years prior to its official discovery at Palomar.[4]Physical characteristicsRotation periodIn July 2011, a rotational lightcurve of Bobbywilliams was obtained from photometric observations by astronomer Julian Oey at both the Australian Kingsgrove ({{small|E19}}) and Leura ({{small|E17}}) observatories. Lightcurve analysis gave a well-defined rotation period of {{val|4.8341}} hours with a brightness variation of 0.05 magnitude ({{small|U=3}}).[8] Diameter and albedoThe Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 4.71 kilometers with an absolute magnitude of 14.0.[5] NamingThis minor planet was named for Jet Propulsion Laboratory engineer Bobby G. Williams (born 1951), specialized in celestial mechanics and the navigation of space probes. He has been a leading navigation manager when NEAR Shoemaker had its rendezvous with the asteroids 253 Mathilde and 433 Eros,[2] The official naming citation was published by the Minor Planet Center on 28 July 1999 ({{small|M.P.C. 35483}}).[21] References1. ^1 2 3 {{cite book |title = Dictionary of Minor Planet Names – (5642) Bobbywilliams |last = Schmadel | first = Lutz D. |publisher = Springer Berlin Heidelberg |pages = 478–479 |date = 2007 |isbn = 978-3-540-00238-3 |doi = 10.1007/978-3-540-29925-7_5346 |chapter = (5642) Bobbywilliams }} [1][2][3][4][5][6]2. ^1 2 3 {{cite web |title = 5642 Bobbywilliams (1990 OK1) |work = Minor Planet Center |url = http://www.minorplanetcenter.net/db_search/show_object?object_id=5642 |accessdate = 1 August 2016}} 3. ^1 {{cite web |title = MPC/MPO/MPS Archive |work = Minor Planet Center |url = http://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html |accessdate = 1 August 2016}} 4. ^1 2 3 4 5 6 {{cite web |title = LCDB Data for (5642) Bobbywilliams |publisher = Asteroid Lightcurve Database (LCDB) |url = http://www.minorplanet.info/PHP/GenerateALCDEFPage_Local.php?AstInfo=5642%7CBobbywilliams |accessdate = 1 August 2016}} 5. ^1 2 {{cite journal |author = Oey, Julian |date = July 2012 |title = Lightcurve Analysis of Asteroids Observed in 2011 from Leura and Kingsgrove Observatories |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011MPBu...38..221O |journal = The Minor Planet Bulletin |volume = 39 |issue = 3 |pages = 145–147 |issn = 1052-8091 |bibcode = 2012MPBu...39..145O |access-date= 1 August 2016}} 6. ^1 {{cite journal |display-authors = 6 |first1 = Peter |last1 = Veres |first2 = Robert |last2 = Jedicke |first3 = Alan |last3 = Fitzsimmons |first4 = Larry |last4 = Denneau |first5 = Mikael |last5 = Granvik |first6 = Bryce |last6 = Bolin |first7 = Serge |last7 = Chastel |first8 = Richard J. |last8 = Wainscoat |first9 = William S. |last9 = Burgett |first10 = Kenneth C. |last10 = Chambers |first11 = Heather |last11 = Flewelling |first12 = Nick |last12 = Kaiser |first13 = Eugen A. |last13 = Magnier |first14 = Jeff S. |last14 = Morgan |first15 = Paul A. |last15 = Price |first16 = John L. |last16 = Tonry |first17 = Christopher |last17 = Waters |date = November 2015 |title = Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V |journal = Icarus |volume = 261 |pages = 34–47 |bibcode = 2015Icar..261...34V |doi = 10.1016/j.icarus.2015.08.007 |arxiv = 1506.00762 |access-date= 1 August 2016}} }} External links
5 : Mars-crossing asteroids|Discoveries by Henry E. Holt|Minor planets named for people|Named minor planets|Astronomical objects discovered in 1990 |
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