4902 Thessandrus
Discovery [1] | |
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Discovered by | C. Shoemaker |
Discovery site | Palomar Obs. |
Discovery date | 9 January 1989 |
Designations | |
MPC designation | (4902) Thessandrus |
Pronunciation |
/θɪˈsændrəs/ the-SAN-drəs |
Named after |
Thessander (Greek mythology)[2] |
1989 AN2 · 1985 TK3 | |
Jupiter trojan [1][3] Greek [4] · background [5] | |
Orbital characteristics [3] | |
Epoch 23 March 2018 (JD 2458200.5) | |
Uncertainty parameter 0 | |
Observation arc | 64.23 yr (23,459 d) |
Aphelion | 5.4234 AU |
Perihelion | 4.9858 AU |
5.2046 AU | |
Eccentricity | 0.0420 |
11.87 yr (4,337 d) | |
204.25° | |
0° 4m 58.8s / day | |
Inclination | 9.0728° |
170.29° | |
270.62° | |
Jupiter MOID | 0.1982 AU |
TJupiter | 2.9730 |
Physical characteristics | |
Mean diameter |
±0.66 km 51.26[6] 61.04 km (calculated)[7] ±2.84 km 71.79[8] |
±20 h 738[9] | |
0.057(assumed)[7] ±0.006 0.060[8] ±0.012 0.081[6] | |
D (Pan-STARRS)[7][10] D (SDSS-MOC)[11] V–I = ±0.044 0.960[7] | |
9.60[8] 9.8[1][3][7][6] | |
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4902 Thessandrus (/θɪˈsændrəs/ the-SAN-drəs), provisionally designated 1989 AN2, is a Jupiter trojan from the Greek camp, approximately 60 kilometers (37 miles) in diameter. It was discovered on 9 January 1989, by American astronomer Carolyn Shoemaker at the Palomar Observatory in California, and later named after Thessander (Thessandrus) from Greek mythology.[2] The dark D-type asteroid is an exceptionally slow rotator and tumbler. It belongs to the 70 largest Jupiter trojans.
Orbit and classification
Thessandrus is a dark Jovian asteroid orbiting in the leading Greek camp at Jupiter's L4 Lagrangian point, 60° ahead of the Gas Giant's orbit in a 1:1 resonance .[4] It is also a non-family asteroid in the Jovian background population.[5]
It orbits the Sun at a distance of 5.0–5.4 AU once every 11 years and 10 months (4,337 days; semi-major axis of 5.2 AU). Its orbit has an eccentricity of 0.04 and an inclination of 9° with respect to the ecliptic.[3]
A first precovery was taken at the discovering observatory in 1954, extending the body's observation arc by 35 years prior to its official discovery observation.[1]
Physical characteristics
Thessandrus has been characterized as a D-type asteroid by Pan-STARRS' survey.[7][10] It is also a D-type in the SDSS-based taxonomy.[11]
Slow rotator
In February 2013, a rotational lightcurve of Thessandrus was obtained from photometric observations by American astronomer Robert Stephens at the Center for Solar System Studies (U81) in California. It gave an exceptionally long rotation period of ±20 hours with a brightness variation of 0.60 in 738magnitude (U=2).[9] It belongs to the slowest rotators known to exist.
Tumbler
The astronomers also detected a non-principal axis rotation seen in distinct rotational cycles in successive order. This is commonly known as tumbling.[9] Thessandrus is the fourth-largest asteroid and largest Jupiter trojan known to be is such a state (also see List of tumblers).
Diameter and albedo
According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Thessandrus measures between 51.26 and 71.79 kilometers in diameter and its surface has an albedo between 0.060 and 0.081.[6][8]
The Collaborative Asteroid Lightcurve Link assumes a standard albedo of a carbonaceous asteroid of 0.057 and calculates a diameter of 61.04 kilometers based on an absolute magnitude of 9.8.[7]
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Naming
This minor planet is named after Thessander (Thessandrus) from Greek mythology and Homer's Iliad. Together with 30 other Greek soldiers he hid in the Trojan horse's belly.[2] The official naming citation was published by the Minor Planet Center on 4 June 1993 (M.P.C. 22248).[12]
References
- 1 2 3 4 "4902 Thessandrus (1989 AN2)". Minor Planet Center. Retrieved 17 June 2018.
- 1 2 3 Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (4902) Thessandrus. Springer Berlin Heidelberg. p. 423. ISBN 978-3-540-00238-3. Retrieved 30 June 2016.
- 1 2 3 4 "JPL Small-Body Database Browser: 4902 Thessandrus (1989 AN2)" (2018-05-20 last obs.). Jet Propulsion Laboratory. Retrieved 17 June 2018.
- 1 2 "List of Jupiter Trojans". Minor Planet Center. 1 June 2018. Retrieved 17 June 2018.
- 1 2 "Asteroid (4902) Thessandrus – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 17 June 2018.
- 1 2 3 4 Grav, T.; Mainzer, A. K.; Bauer, J. M.; Masiero, J. R.; Nugent, C. R. (November 2012). "WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy". The Astrophysical Journal. 759 (1): 10. arXiv:1209.1549. Bibcode:2012ApJ...759...49G. doi:10.1088/0004-637X/759/1/49. Retrieved 17 June 2018. (online catalog)
- 1 2 3 4 5 6 7 "LCDB Data for (4902) Thessandrus". Asteroid Lightcurve Database (LCDB). Retrieved 30 June 2016.
- 1 2 3 4 Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 17 June 2018. (online, AcuA catalog p. 153)
- 1 2 3 French, Linda M.; Stephens, Robert, D.; Coley, Daniel R.; Wasserman, Lawrence H.; Vilas, Faith; La Rocca, Daniel (October 2013). "A Troop of Trojans: Photometry of 24 Jovian Trojan Asteroids". The Minor Planet Bulletin. 40 (4): 198–203. Bibcode:2013MPBu...40..198F. ISSN 1052-8091. Retrieved 30 June 2016.
- 1 2 Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results" (PDF). Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 17 June 2018.
- 1 2 Carvano, J. M.; Hasselmann, P. H.; Lazzaro, D.; Mothé-Diniz, T. (February 2010). "SDSS-based taxonomic classification and orbital distribution of main belt asteroids". Astronomy and Astrophysics. 510: 12. Bibcode:2010A&A...510A..43C. doi:10.1051/0004-6361/200913322. Retrieved 12 June 2018.
- ↑ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 17 June 2018.
External links
- Asteroid Lightcurve Database (LCDB), query form (info)
- Dictionary of Minor Planet Names, Google books
- Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
- Asteroid 4902 Thessandrus at the Small Bodies Data Ferret
- 4902 Thessandrus at AstDyS-2, Asteroids—Dynamic Site
- 4902 Thessandrus at the JPL Small-Body Database