2009 SE
Small asteroid and Mars trojan
From Wikipedia, the free encyclopedia
2009 SE is a small asteroid and Mars trojan orbiting near the L5 point of Mars (60 degrees behind Mars on its orbit).[2]
| Discovery | |
|---|---|
| Discovered by | Catalina Sky Survey |
| Discovery date | 16 September 2009 |
| Designations | |
| 2009 SE | |
| Martian L5 | |
| Orbital characteristics[1] | |
| Epoch 21 November 2025 (JD 2461000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 5,498 days (15.05 yr) |
| Aphelion | 1.623690 AU (242.9006 Gm) |
| Perihelion | 1.425183 AU (213.2043 Gm) |
| 1.524436 AU (228.0524 Gm) | |
| Eccentricity | 0.0651085 |
| 1.88 yr (687.484 d) | |
| 208.166° | |
| 0° 31m 25.136s /day | |
| Inclination | 20.6248° |
| 6.79202° | |
| 354.169° | |
| Earth MOID | 0.42305 AU (63.287 Gm) |
| Jupiter MOID | 3.53237 AU (528.435 Gm) |
| Physical characteristics | |
| 400 m | |
| 0.5–0.05 (assumed) | |
| 20.13 | |
Discovery, orbit and physical properties
2009 SE was first observed on 16 September 2009 by the Catalina Sky Survey (CSS).[3] Its orbit is characterized by low eccentricity (0.065), moderate inclination (20.6°) and a semi-major axis of 1.52 AU.[3] Upon discovery, it was classified as Mars-crosser by the Minor Planet Center. Its orbit is well determined as it is currently (as of November 2025) based on 60 observations with a data-arc span of 5,498 days.[1] 2009 SE has an absolute magnitude of 20.13 which gives a characteristic diameter of 400 m.[1]
Mars trojan and orbital evolution
Recent calculations indicate that it is a stable L5 Mars trojan with a libration period of 1430 yr and an amplitude of 70°.[2] The libration amplitude is not similar to that of 5261 Eureka and related objects.[citation needed]
