9142 Rhesus
Minorplanetyes
Background
  1. C2FFFF
DiscovererC. J. van Houten
I. van Houten-G.
T. Gehrels
Discovery sitePalomar Obs.
Discovered16 October 1977
Mpc name(9142) Rhesus
Alt names5191 T-3 · 1988 RX
Pronounced/ˈriːsəs/[1]
Named afterRhesus of Thrace[2]
(Greek mythology)
Mp categoryJupiter trojan[2][3]
Trojan[4] · background[5]
Epoch23 March 2018 (JD 2458200.5)
Uncertainty0
Observation arc63.18 yr (23,076 d)
Aphelion5.8403 AU
Perihelion4.5017 AU
Semimajor5.1710 AU
Eccentricity0.1294
Period11.76 yr (4,295 d)
Mean anomaly199.27°
Mean motion/ day
Inclination12.801°
Asc node141.18°
Arg peri173.17°
Jupiter moid0.4321 AU
Tisserand2.9340
Mean diameter42.31 ± 0.46 km[6]
Rotation7.325 ± 0.0021 h[7][8]
Albedo0.062[6]
Abs magnitude10.5[6]
10.6[2][3]

9142 Rhesus /ˈriːsəs/ is a larger Jupiter trojan from the Trojan camp, approximately 42 kilometers (26 miles) in diameter. It was discovered during the third Palomar–Leiden Trojan survey in 1977, and later named after King Rhesus from Greek mythology.[2] The dark D-type asteroid has a rotation period of 7.3 hours.[7]

Discovery

Rhesus was discovered on 16 October 1977, by Dutch astronomer couple Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by Dutch–American astronomer Tom Gehrels at the Palomar Observatory in California. The body's observation arc begins with its first observation, a precovery taken at Palomar in December 1954.[2]

Palomar–Leiden survey

The survey designation "T-3" stands for the third Palomar–Leiden Trojan survey, named after the fruitful collaboration of the Palomar and Leiden Observatory in the 1960s and 1970s. Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out. The trio are credited with the discovery of several thousand asteroids.[9]

Orbit and classification

Rhesus is a dark Jovian asteroid in a 1:1 orbital resonance with Jupiter. It is located in the trailering Trojan camp at the Gas Giant's Lagrangian point, 60° behind its orbit ((see Trojans in astronomy)).[4] It orbits the Sun at a distance of 4.5–5.8 AU once every 11 years and 9 months (4,295 days; semi-major axis of 5.17 AU). Its orbit has an eccentricity of 0.13 and an inclination of 13° with respect to the ecliptic.[3]

Naming

This minor planet was named from Greek mythology after King Rhesus of Thrace an ally of the Trojans against the Greeks in the Trojan War. He was killed in his sleep by Odysseus and Diomedes who attacked the Thracian camp in the dead of night.[2] The official naming citation was published by the Minor Planet Center on 8 December 1998 (M.P.C. 33389).[10]

Physical characteristics

In the SDSS-based taxonomy, Rhesus is a dark D-type asteroid, the most common type among the Jupiter trojans.[11][12] It has also been classified as a D-type by Pan-STARRS' survey.[7][13]

Rotation period

In August 2012, and September 2013, two rotational lightcurves of Rhesus were obtained from photometric observations in the R-band by astronomers at the Palomar Transient Factory in California. Lightcurve analysis gave a rotation period of 7.325 ± 0.0021 and 7.284 ± 0.0087 hours with a brightness amplitude of 0.27 and 0.24 magnitude, respectively (U=2/2).[7][8]

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Rhesus measures 42.31 kilometers in diameter and its surface has an albedo of 0.062,[6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a shorter diameter of 34.85 kilometers based on an absolute magnitude of 11.02.[7]

References

  1. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  2. ^ "9142 Rhesus (5191 T-3)". Minor Planet Center. Retrieved 25 June 2018.
  3. ^ "JPL Small-Body Database Browser: 9142 Rhesus (5191 T-3)" (2018-02-25 last obs.). Jet Propulsion Laboratory. Retrieved 25 June 2018.
  4. ^ Carruba, V. (1 June 2018). "List of Jupiter Trojans". Minor Planet Center. Retrieved 25 June 2018.
  5. ^ "Asteroid (9142) Rhesus – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 25 June 2018.
  6. ^ 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. S2CID 119101711 (online catalog)
  7. ^ No. 9142. Retrieved 25 June 2018.
  8. ^ Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. S2CID 8342929
  9. ^ "Minor Planet Discoverers (by number)". Minor Planet Center. 31 May 2018. Retrieved 25 June 2018.
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 25 June 2018.
  11. ^ 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 30 October 2019. (PDS data set)
  12. ^ "Asteroid 9142 Rhesus". Small Bodies Data Ferret. Retrieved 25 June 2018.
  13. ^ 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". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. S2CID 53493339