(21900) Orus
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Asteroid (21900) Orus |
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|---|---|
| Properties of the orbit ( animation ) | |
| Orbit type | Jupiter Trojan (L 4 ) |
| Major semi-axis | 5.128 AU |
| eccentricity | 0.0356 |
| Perihelion - aphelion | 4.945 AU - 5.310 AU |
| Inclination of the orbit plane | 8.47 ° |
| Length of the ascending node | 258.561 ° |
| Argument of the periapsis | 180.461 ° |
| Time of passage of the perihelion | August 26, 2011 |
| Sidereal period | 11 a 226 d |
| Physical Properties | |
| Medium diameter | 50.81 km |
| Albedo | 0.075 |
| Rotation period | 13.45 ± 0.08 h |
| Absolute brightness | 10.0 mag |
| Spectral class | C. |
| history | |
| Explorer | Takao Kobayashi |
| Date of discovery | November 9, 1999 |
| Another name | 1999 VQ 10 , 1998 VD 18 |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items. | |
(21900) Orus is an asteroid belonging to the group of Trojans . It is used to describe asteroids that move on the orbit of Jupiter around the sun.
Discovery and naming
Orus was discovered by the amateur astronomer Takao Kobayashi at his private Ōizumi observatory in Ōizumi , Gunma Prefecture , Japan . The asteroid was given its final name on February 22, 2016.
Oros was an Achaean warrior and lord of the city of Argos from Greek mythology in Homer's Iliad , who was killed and sacrificed by the Trojan prince Hector during the Trojan War . The largest Trojan asteroid is named after the latter . A town in the Pyrenees in southern France
also bears this name.
Track properties
Orus is located near Jupiter's Lagrange point L 4 and thus belongs to the Greek group of Trojans that hurry ahead of the planet. Its orbit runs between 4.945 ( perihelion ) and 5.310 ( aphelion ) astronomical units and is about 8.5 ° inclined to the ecliptic . The orbital eccentricity is 0.036.
The rotation period is 13 hours and 27 minutes, based on light curve observations with the 1.2-meter telescope at the Calar Alto Observatory in Spain from October 2009 by astronomer Stefano Mottola, during which 80 Jupiter Trojans were examined.
Physical Properties
The asteroid belongs to the class of the C-type asteroids and is therefore likely to consist of a material similar to the carbonaceous chondrites .
At present, it is assumed that it has a diameter of almost 51 km. This value is based on an assumed reflectivity of 7.5% and an absolute brightness of 10.0 mag. Other calculations gave an albedo of 8.3%, which would result in a diameter of 53.9 km. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for C asteroids of 5.7%, which would correspond to a diameter of 55.7 km.
exploration
After his discovery, Orus was able to use photos to date back to 1951 and thus calculate his orbit. Since then, the asteroid has been observed through various telescopes, a total of 1,127 times so far.
On January 4, 2017, NASA decided to deploy the Lucy space probe , which is scheduled to launch in October 2021 and reach Orus in October 2028. In addition to Orus, the L 4 Trojans (3548) Eurybates , (15094) Polymele and (11351) Leucus will also be examined between 2027 and 2028 . The probe will then swing-by the Earth to reach the L 5 double Trojans (617) Patroclus and Menoetius in March 2033. The objective of the mission is a more precise determination of the shape and size as well as the rotation and the spectroscopic properties of the asteroids mentioned.
See also
Individual evidence
- ^ Rotational properties of Jupiter Trojans. I. Light curves of 80 objects
- ↑ Neowise Studies of spectrophotometrically classified asteroids: preliminary results
- ↑ (21900) Orus in the Small-Body Database of the Jet Propulsion Laboratory (English). (As of February 2017)