121 Hermione

Main-belt asteroid binary September 2018 yes 121 Hermione #D6D6D6 121 Hermione and its moon James Craig Watson 12 May 1872 (121) Hermione A872 JA; 1970 VE h ɜːr ˈ m aɪ . ə n iːNoah Webster (1884) A Practical Dictionary of the English Language Hermionean h ɜːr m aɪ . ə ˈ n iː ə n Hermione(Greek mythology) main-beltCybele 23 March 2018 (JD 2458200.5) 0 145.96 yr (53,312 d) 3.9067 AU 2.9889 AU 3.4478 AU 0.1331 6.40 yr (2,338 d) 157.08° 0.1540 ms / day 7.5975° 73.127° 298.18° S/2002 (121) 1 268 × 186 × 183 km2008 Recent Asteroid Mass Determinations Personal Website Jim Baer http://home.earthlink.net/~jimbaer1/astmass.txt 2008-12-07 https://web.archive.org/web/20130702212735/http://home.earthlink.net/~jimbaer1/astmass.txt 2 July 2013 dead (254 ± 4) × (125 ± 9) kmF. Marchis Shape, size and multiplicity of main-belt asteroids I. Keck Adaptive Optics survey Icarus 185 39–63 2006 10.1016/j.icarus.2006.06.001 19081813 1 2600456 2006Icar..185...39M etal 95 km 3.0 0.4 6 km3 5.381 5 18 kg %F. Marchis Mass and density of Asteroid 121 Hermione from an analysis of its companion orbit Icarus 178 450–464 2005 10.1016/j.icarus.2005.05.003 2005Icar..178..450M 2 etal 1.8 ± 0.2 g/cm3snowman Using the "snowman" shape model, which best matches the value of J2 implied from precession. 0.022 m/s2pointyend On the extremities of the long axis. 0.075 km/spointyend 0.2313 d (5.551 h)IAUC 8264 https://web.archive.org/web/20080709060512/http://cfa-www.harvard.edu/iauc/08200/08264.html#Item1 9 July 2008 73° +10 ± 2° 1.5 ± 2° 0.0482 ± 0.002Supplemental IRAS minor planet survey https://web.archive.org/web/20090817051318/http://www.psi.edu/pds/resource/imps.html 2009-08-17 CPDS node taxonomy database https://web.archive.org/web/20090805185511/http://www.psi.edu/pds/resource/taxonomy.html 2009-08-05 7.31 121 Hermione is a very large binary asteroid discovered in 1872. It orbits in the Cybele group in the far outer asteroid belt. As an asteroid of the dark C spectral type, it is probably composed of carbonaceous materials. In 2002, a small moon was found to be orbiting Hermione.Linda T. Elkins-Tanton Asteroids, Meteorites, and Comets https://books.google.com/books?id=K-0xBsMsursC&pg=PA96 2010 Infobase Publishing 978-1-4381-3186-3 96 Discovery Hermione was discovered by J. C. Watson on 12 May 1872 from Ann Arbor, Michigan, in the United States, and named after Hermione, daughter of Menelaus and Helen in Greek mythology. Physical properties thumb|left|Lightcurve-based 3D-model of Hermione left|thumb|Lightcurve-based 3D-model of Hermione on the top and an image of the asteroid on the bottom. The asteroid has a bi-lobed shape, as evidenced by adaptive optics images, the first of which were taken in December 2003 with the Keck telescope. Of several proposed shape models that agreed with the images, a "snowman"-like shape was found to best fit the observed precession rate of Hermione's satellite. In this "snowman" model, the asteroid's shape can be approximated by two partially overlapping spheres of radii 80 and 60 km, whose centers are separated by a distance of 115 km. A simple ellipsoid shape was ruled out. Observation of the satellite's orbit has made possible an accurate determination of Hermione's mass. For the best-fit "snowman" model, the density is found to be 1.8 ± 0.2 g/cm3, giving a porosity on the order of 20%, and possibly indicating that the main components are fractured solid bodies, rather than the asteroid being a rubble pile. Occultations by Hermione have been successfully observed three times so far, the last time in February 2004. S/2002 (121) 1 #A0FFA0 yes IAUC 7980 https://web.archive.org/web/20060501175811/http://cfa-www.harvard.edu/iauc/07900/07980.html 2006-05-01 W. J. Merline,P. M. Tamblyn,C. Dumas,L. M. Close,C. R. Chapman,F. Menard,W. M. Owen,and D. C. Slater 2002-09-28 LaFayette main-beltCybele 121 Hermione and S/2002 (121) 1, orbit data website maintained by F. Marchis. 768 ± 11 km 0.001 ± 0.001 2.582 ± 0.002 d 121 Hermione 3 ± 2°(with respect to Hermione pole) 12 ± 4 km ~1.615 kg"mass" Assuming a similar density to the primary. 13.0 Moon A satellite of Hermione was discovered in 2002 with the Keck II telescope. It is about 8 miles (13 km) in diameter. The satellite is provisionally designated S/2002 (121) 1. It has not yet been officially named, but "LaFayette" has been proposed by a group of astronomers in reference to the frigate used in secret by Marquis de Lafayette to reach America to help the insurgents. Notes References 30em 2018-05-25 last obs. JPL Small-Body Database Browser: 121 Hermione https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2000121 Jet Propulsion Laboratory 14 September 2018 Schmadel Lutz D. Dictionary of Minor Planet Names Springer Berlin Heidelberg 26 2007 978-3-540-00238-3 10.1007/978-3-540-29925-7_122 (121) Hermione 121 Hermione Minor Planet Center https://www.minorplanetcenter.net/db_search/show_object?object_id=121 14 September 2018 (121) Hermione and S/2002 (121) 1 ("LaFayette") http://www.johnstonsarchive.net/astro/astmoons/am-00121.html Wm. Robert Johnston Asteroids with Satellites Database Johnston's Archive 21 September 2014 7 November 2021 External links 121 Hermione and S/2002 (121) 1, orbit data website maintained by F. Marchis. Includes adaptive optics images, orbit diagrams, and shape models. (121) Hermione, datasheet, johnstonsarchive.net Asteroids with Satellites, Robert Johnston, johnstonsarchive.net Tally of Asteroids Harboring Moons Grows Beyond 30 (Space.com, 3 October 2002) 121 120 Lachesis 121 122 Gerda 000121 Category:Discoveries by James Craig Watson Category:Named minor planets 000121 000121 000121 000121 18720512