15094 Polymele

Jupiter trojan asteroid March 2018 yes 15094 Polymele #C2FFFF 15094 Polymele Hubble.jpg Polymele imaged by the Hubble Space Telescope in 2018 17 November 1999 Catalina Sky Survey Catalina Station (15094) Polymele 1999 WB 21997 WR 57 p ɒ l ᵻ ˈ m iː l iː'Polymela' in Noah Webster (1884) A Practical Dictionary of the English Language Polymele(Greek mythology) Jupiter trojan(Greek camp) 25 February 2023 (JD 2460000.5) 0 30 November 1951 5.682 AU 4.679 AU 5.180 AU 0.0968 11.79 yr (4,307 d) 44.314° 0.0835933 ms / day 12.981° 50.319° 4.772° 0.2445 AU 2.940 1 ("Shaun") 27.0 x 24.4 x 10.4 km(± 2.0 x 1.6 x 1.6 km) 21.075 0.136 km 5.8607 0.0005 h 11.5 0.1 h 0.7 - 1 g/cm3 (assumed) -80.9 2.1 ° 231.8 4.5 ° 170.9 ° (wrt ecliptic) 0.0730.091 0.017 PB–V 0.652 0.065V–R 0.477 0.065V–I 0.799 0.068 11.6011.691 0.002 (S/R) 15094 Polymele p ɒ l @ ˈ m iː l iː is a primitive Jupiter trojan from the Greek camp, approximately 21 km mi off us in diameter. It is a target of the Lucy mission with a close flyby planned to occur in September 2027. It was discovered on 17 November 1999, by astronomers with the Catalina Sky Survey at Mount Lemmon Observatory, Arizona, in the United States. The P-type asteroid has a rotation period of 5.9 hours and highly flattened shape. It was named after Polymele from Greek mythology, the wife of Menoetius and the mother of Patroclus. In 2022, it was reported to have a natural satellite approximately 5 km mi off us in diameter. Orbit and classification Polymele is a Jupiter trojan asteroid orbiting in the leading Greek camp at Jupiter's Lagrangian point, 60° ahead of the gas giant's orbit (see Trojans in astronomy). It orbits the Sun at a distance of 4.7–5.7 AU once every 11 years and 9 months (4,289 days; semi-major axis of 5.17 AU). Its orbit has an eccentricity of 0.09 and an inclination of 13° with respect to the ecliptic. The asteroid's observation arc begins 48 years prior to its official discovery observation at Mount Lemmon, with a precovery taken at Palomar Observatory in 1951, and published by the Digitized Sky Survey later on. Naming This minor planet was named after Polymele, the daughter of Peleus from Greek mythology. According to the Latin author Gaius Julius Hyginus ( 64 BC – AD 17), she is the wife of the Argonaut Menoetius and the mother of Patroclus, who participated in the Trojan War. Polymele is also known as "Philomela"; that name was previously used for the asteroid 196 Philomela. The approved naming citation was published by the Minor Planet Center on 22 February 2016 (M.P.C. 98711). Physical characteristics Polymele has been characterized as a primitive P-type asteroid by the investigators of the Lucy mission. P-type asteroids are known for their low albedo. It has a V–I color index of 0.799, which is lower than that for most larger Jupiter trojans (see table below). Size, shape, and albedo According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Polymele measures 21.075 kilometers in diameter and its surface has an albedo of 0.091, while in 2018, Marc Buie published an albedo of 0.073 and an absolute magnitude of 11.691 in the S- and/or R band. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a larger diameter of 26.64 kilometers based on an absolute magnitude of 11.6. On 27 March 2022, multiple astronomers observed a stellar occultation by Polymele, which revealed an apparently elongated projected shape with projected dimensions of 26.2 x 12.8 km mi. Additional occultation observations of Polymele from 2020 to 2023 revealed that Polymele's true shape is a highly flattened disk with dimensions 27.0 x 24.4 x 10.4 km mi, similar to the large flat lobe of the Kuiper belt object 486958 Arrokoth. This unusual flattened shape of Polymele implies that it had retained its original shape from when it formed by accretion. Rotation In March 2016, a rotational lightcurve of Polymele was obtained from photometric observations by Marc Buie and colleagues. Lightcurve analysis gave a rotation period of 5.8607 0.0005 hours with a small brightness amplitude of 0.09 0.03 magnitude (U=2-), which indicates the body is being viewed pole-on. Previously, the Lucy mission team published spin rates of 6.1 and 4 hours, respectively. In a 2021 paper, the Lucy team published a rotation period of 11.5 0.1 hours, implying that the previous period may have been an alias. The resolved observation of Polymele's shape in multiple occultation events allowed the Lucy team to determine the orientation of Polymele's rotational pole. Polymele's rotational north pole points toward ecliptic latitude –80.9°, which corresponds to an axial tilt of 170.9° with respect to the ecliptic, making Polymele a retrograde rotator. Satellite thumb|left|upright=1.5|Discovery of Polymele's satellite in the 27 March 2022 occultation + Diameter specifications for S/2022 (15094) 1 Year Dimensions (km) Source 2022 5.0 M. Buie u. a. Following observations of an occultation on 26 March 2022, the Lucy mission team reported the discovery of a natural satellite around Polymele. The satellite is a smaller asteroid about 5–6 km mi off us in diameter, orbiting nearly in the equatorial plane of Polymele at a distance of 204.4 ± 2.6 km mi. Assuming Polymele has a density of 0.7 - 1 g/cm3, the satellite should have an orbital period between 14.4 and 16.6 days. It will not be assigned a formal name until further observations determine its orbit.NASA's Lucy Team Discovers Moon Around Asteroid Polymele https://www.nasa.gov/feature/goddard/2022/nasa-s-lucy-team-discovers-moon-around-asteroid-polymele/ NASA 16 August 2022 17 August 2022 The Lucy team refers to the companion by the temporary informal name "Shaun", after Aardman Animations' animated sheep. The satellite was detected again in an occultation on 4 February 2023, in the largest organized occultation expedition in history. Nearly 200 astronomers across two continents participated in the campaign.NASA/SwRI Spotting a Satellite - Lucy Mission https://lucy.swri.edu/SpottingASatellite.html LUCY Mission Page 1 September 2023 Exploration Lucy mission target Polymele is planned to be visited by the Lucy spacecraft which launched in 2021. The flyby is scheduled for 15 September 2027, and will approach the asteroid to a distance of 415 km mi at a relative velocity of 6 km/s mph. References 30em 2015-06-10 last obs. JPL Small-Body Database Browser: 15094 Polymele (1999 WB2) https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2015094 Jet Propulsion Laboratory 26 September 2018 15094 Polymele (1999 WB2) Minor Planet Center https://www.minorplanetcenter.net/db_search/show_object?object_id=15094 8 March 2018 List of Jupiter Trojans Minor Planet Center 20 June 2016 https://www.minorplanetcenter.net/iau/lists/JupiterTrojans.html 8 March 2018 MPC/MPO/MPS Archive Minor Planet Center https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html 8 March 2018 T. Grav A. K. Mainzer J. M. Bauer J. R. Masiero C. R. Nugent November 2012 WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy The Astrophysical Journal 759 1 10 2012ApJ...759...49G 10.1088/0004-637X/759/1/49 1209.1549 119101711 (online catalog) Ninth asteroid added to Lucy mission; optimism grows on solar array issue 14 June 2022 Clark, Stephen Spaceflight Now https://spaceflightnow.com/2022/06/14/nasa-making-progress-deploying-stuck-solar-panel-on-lucy-asteroid-probe 15 June 2022 15094 26 September 2018 6 A. K. Mainzer J. M. Bauer R. M. Cutri T. Grav E. A. Kramer J. R. Masiero C. R. Nugent S. M. Sonnett R. A. Stevenson E. L. Wright June 2016 NEOWISE Diameters and Albedos V1.0 https://sbnarchive.psi.edu/pds3/non_mission/EAR_A_COMPIL_5_NEOWISEDIAM_V1_0/data/neowise_jupiter_trojans.tab NASA Planetary Data System 247 EAR-A-COMPIL-5-NEOWISEDIAM-V1.0 2016PDSS..247.....M 26 September 2018 6 A. Mainzer T. Grav J. Masiero E. Hand J. Bauer D. Tholen R. S. McMillan T. Spahr R. M. Cutri E. Wright J. Watkins W. Mo C. Maleszewski November 2011 NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results The Astrophysical Journal 741 2 25 2011ApJ...741...90M 10.1088/0004-637X/741/2/90 1109.6407 118700974 (catalog) Marc W. Buie Amanda M. Zangari Simone Marchi Harold F. Levison Stefano Mottola June 2018 Light Curves of Lucy Targets: Leucus and Polymele https://www.cfca.nao.ac.jp/~tito/misc/ncpdas/20180625-Buie.pdf The Astronomical Journal 155 6 11 2018AJ....155..245B 10.3847/1538-3881/aabd81 26 September 2018 free H. F. Levison C. Olkin K. S. Noll S. Marchi Lucy Team March 2017 Lucy: Surveying the Diversity of the Trojan Asteroids: The Fossils of Planet Formation https://www.hou.usra.edu/meetings/lpsc2017/pdf/2025.pdf 48th Lunar and Planetary Science Conference 1964 2025 2017LPI....48.2025L 13 April 2017 Marc W. Buie Amanda Marie Zangari Simone Marchi Stefano Mottola Harold F. Levison October 2016 Ground-based characterization of Leucus and Polymele, two fly-by targets of the Lucy Discovery mission American Astronomical Society 48 208.06 2016DPS....4820806B O. R. Hainaut H. Boehnhardt S. Protopapa October 2012 Colours of minor bodies in the outer solar system. II. A statistical analysis revisited Astronomy and Astrophysics 546 20 2012A&A...546A.115H 10.1051/0004-6361/201219566 1209.1896 54776793 etal Marc Buie Brian Keeney Harold Levison Catherine Olkin Shape and duplicity of Lucy Mission target Polymele from occultation observations https://baas.aas.org/pub/2022n8i512p03/release/1 54th Annual DPS Meeting American Astronomical Society December 2022 54 8 512.03 2022DPS....5451203B 28 January 2023 etal H. F. Levison M. W. Buie B. A. Keeney S. Mottola Interpreting the Stellar Occultations of (15094) Polymele – a Lucy Target https://www.hou.usra.edu/meetings/acm2023/pdf/2184.pdf Asteroids, Comets, Meteors Conference 2023 Lunar and Planetary Institute 2851 June 2023 etal M. W. Buie B. A. Keeney H. F. Levison Occultation results for the (15094) Polymele system – a Lucy Target https://www.hou.usra.edu/meetings/acm2023/pdf/2184.pdf Asteroids, Comets, Meteors Conference 2023 Lunar and Planetary Institute 2851 June 2023 H. F. Levison C. Olkin K. S. Noll S. Marchi the Lucy Science Team October 2021 Lucy Mission to the Trojan Asteroids: Science Goals https://iopscience.iop.org/article/10.3847/PSJ/abf840/pdf Planetary Science Journal 2 13 2021PSJ.....2..171L 16 October 2024 External links Asteroid Lightcurve Database (LCDB), query form (info https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html 16 December 2017 ) Dictionary of Minor Planet Names, Google books Discovery Circumstances: Numbered Minor Planets (15001)-(20000) – Minor Planet Center 15094 15093 Lestermackey 15094 015094 015094 Category:Named minor planets 015094 19991117