Astronomy:5258 Rhoeo

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5258 Rhoeo
Discovery [1]
Discovered byY. Oshima
Discovery siteGekko Obs.
Discovery date1 January 1989
Designations
(5258) Rhoeo
Named afterRhoeo
(Greek mythology)[2]
1989 AU1
Minor planet categoryJupiter trojan[1][3]
Greek [4] · Eurybates [5]
AdjectivesRhoe(i)an
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc29.39 yr (10,734 d)
|{{{apsis}}}|helion}}5.5669 AU
|{{{apsis}}}|helion}}4.7879 AU
5.1774 AU
Eccentricity0.0752
Orbital period11.78 yr (4,303 d)
Mean anomaly156.16°
Mean motion0° 5m 1.32s / day
Inclination5.9179°
Longitude of ascending node248.11°
230.22°
Jupiter MOID0.0912 AU
TJupiter2.9840
Physical characteristics
Mean diameter50.77 km (calculated)[6]
53.28±4.43 km[7]
Rotation period19.85±0.05 h[8]
Geometric albedo0.052±0.014[7]
0.057 (assumed)[6]
C (assumed)[6]
V–R = 0.466±0.041[9]
V–I = 1.010±0.050[6]
Absolute magnitude (H)10.2[1][3][6][7]


5258 Rhoeo, provisional designation: 1989 AU1, is a Jupiter trojan and member of the Eurybates family from the Greek camp, approximately 53 kilometers (33 miles) in diameter. It was discovered on 1 January 1989, by Japanese astronomer Yoshiaki Oshima at the Gekko Observatory, east of Shizuoka, Japan.[1] The assumed C-type asteroid belongs to the 90 largest Jupiter trojans and has a rotation period of 19.9 hours.[6] It was named from Greek mythology after Rhoeo, lover of Apollo and mother of his son Anius.[2]

Orbit and classification

Rhoeo 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 (see Trojans in astronomy).[4][10] It orbits the Sun at a distance of 4.8–5.6 AU once every 11 years and 9 months (4,303 days; semi-major axis of 5.18 AU). Its orbit has an eccentricity of 0.08 and an inclination of 6° with respect to the ecliptic.[3] The body's observation arc begins with its official discovery observation at Gekko Observatory in January 1989.[1]

Eurybates family

Rhoeo is the member of the small Eurybates family (005),[5] named after its parent body, 3548 Eurybates. This asteroid family comprises 218 known members of carbonaceous and/or primitive composition,[11]:23 and is one of only a few families identified among the Jovian asteroids; with four of them in the Greek camp. This potentially collisional family was first characterized by Jakub Rozehnal and Miroslav Brož in 2011, and further described in 2014.[12][13] Other members of this family include the Jupiter trojans 8060 Anius, 9818 Eurymachos, (163189) 2002 EU6, (287577) 2003 FE42 and 360072 Alcimedon.[11] In the HCM analysis by Milani and Knežević, however, Rhoeo belongs to the background population.[10]

Numbering and naming

This minor planet was numbered by the Minor Planet Center on 14 July 1992 (M.P.C. 20492).[14] On 14 May 2021, the object was named by the Working Group for Small Bodies Nomenclature (WGSBN), after Rhoeo from Greek mythology, who became the lover of Apollo and by him the mother of Anius. When her father discovered her pregnancy, he believed she was impregnated by a man rather than a god. He placed her in a chest and cast her out to sea. Anius later prophesied the decade-long siege of Troy.[2]

Physical characteristics

Rhoeo is an assumed, carbonaceous C-type asteroid.[6] The overall spectral type of members of the Eurybates family is that of a C- and P-type.[11]:23 It has a high V–I color index of 1.01.[6]

Rotation period

In April 2015, the so-far only lightcurve was obtained by Robert Stephens at the Center for Solar System Studies in Landers, California. The photometric observations gave a rotation period of 19.85±0.05 hours and a brightness variation of 0.14 magnitude ({{{1}}}).[6][8][lower-alpha 1]

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Rhoeo measures 53.28 kilometers in diameter and its surface has an albedo of 0.052,[7] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 50.77 kilometers based on an absolute magnitude of 10.2.[6]

100+ largest Jupiter trojans

Notes

  1. Lightcurve plot of (5258) Rhoeo from Apr 2015 by Robert Stephens at the Center for Solar System Studies (U81). Quality code is 3- (lightcurve rating at CS3). Summary figures at the LCDB and CS3.

References

  1. Jump up to: 1.0 1.1 1.2 1.3 1.4 "5258 (1989 AU1)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=5258. Retrieved 20 June 2018. 
  2. Jump up to: 2.0 2.1 2.2 "WGSBN Bulletin Archive". Working Group for Small Bodies Nomenclature. 14 May 2021. https://www.wgsbn-iau.org/files/Bulletins/index.html. Retrieved 16 May 2021.  (Bulletin #1)
  3. Jump up to: 3.0 3.1 3.2 3.3 "JPL Small-Body Database Browser: 5258 (1989 AU1)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2005258. Retrieved 20 June 2018. 
  4. Jump up to: 4.0 4.1 "List of Jupiter Trojans". Minor Planet Center. 1 June 2018. https://www.minorplanetcenter.net/iau/lists/JupiterTrojans.html. Retrieved 20 June 2018. 
  5. Jump up to: 5.0 5.1 "Asteroid (5258) 1989 AU1". Small Bodies Data Ferret. https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=5258. Retrieved 20 June 2018. 
  6. Jump up to: 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 "LCDB Data for (5258)". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=5258%7C. Retrieved 20 June 2018. 
  7. Jump up to: 7.0 7.1 7.2 7.3 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. doi:10.1088/0004-637X/759/1/49. Bibcode2012ApJ...759...49G.  (online catalog)
  8. Jump up to: 8.0 8.1 Stephens, Robert D.; Coley, Daniel, R.; French, Linda M. (January 2016). "Large L5 Jovian Trojan Asteroid Lightcurves from the Center for Solar System Studies". The Minor Planet Bulletin 43 (1): 15–22. ISSN 1052-8091. Bibcode2016MPBu...43...15S. 
  9. Hainaut, O. R.; Boehnhardt, H.; Protopapa, S. (October 2012). "Colours of minor bodies in the outer solar system. II. A statistical analysis revisited". Astronomy and Astrophysics 546: 20. doi:10.1051/0004-6361/201219566. Bibcode2012A&A...546A.115H. 
  10. Jump up to: 10.0 10.1 "Asteroid (5258) 1989 AU1 – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. https://newton.spacedys.com/astdys/index.php?n=5258&pc=1.1.6. 
  11. Jump up to: 11.0 11.1 11.2 Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families". Asteroids IV. pp. 297–321. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131. Bibcode2015aste.book..297N. 
  12. Broz, M.; Rozehnal, J. (June 2011). "Eurybates – the only asteroid family among Trojans?". Monthly Notices of the Royal Astronomical Society 414 (1): 565–574. doi:10.1111/j.1365-2966.2011.18420.x. Bibcode2011MNRAS.414..565B. 
  13. Rozehnal, J.; Brož, M. (July 2014). "Long-term evolution of asteroid families among Jovian Trojans". Asteroids: 452. Bibcode2014acm..conf..452R. 
  14. "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html. Retrieved 20 June 2018. 

External links