Astronomy:2018 EC4
| Discovery | |
|---|---|
| Discovered by | Mt. Lemmon Survey |
| Discovery date | 10 March 2018 |
| Designations | |
| 2018 EC4 | |
| Minor planet category | Martian L5  |
| Orbital characteristics[1] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 3131 days (8.57 yr) |
| |{{{apsis}}}|helion}} | 1.61579336 astronomical unit|AU (241.719246 Gm) |
| |{{{apsis}}}|helion}} | 1.43135923 AU (214.128293 Gm) |
| 1.52357630 AU (227.923770 Gm) | |
| Eccentricity | 0.06052671 |
| Orbital period | 1.88 yr (686.90193 d) |
| Mean anomaly | 203.4934° |
| Mean motion | 0° 31m 26.732s /day |
| Inclination | 21.835796° |
| Longitude of ascending node | 47.371564° |
| 344.1754° | |
| Earth MOID | 0.443437 AU (66.3372 Gm) |
| Jupiter MOID | 3.54199 AU (529.874 Gm) |
| Physical characteristics | |
| Dimensions | 300 m |
| Geometric albedo | 0.5-0.05 (assumed) |
| Absolute magnitude (H) | 20.1 |
2018 EC4 is a small asteroid and Mars trojan orbiting near the L5 point of Mars (60 degrees behind Mars on its orbit).[2]
Discovery, orbit and physical properties
2018 EC4 was first observed on 10 March 2018 by the Mt. Lemmon Survey, but it had already been imaged (but not identified as an asteroid) by the Pan-STARRS 1 telescope system at Haleakala on 29 October 2011.[3] Its orbit is characterized by low eccentricity (0.061), moderate inclination (21.8°) 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 (January 2021) based on 70 observations with a data-arc span of 3,131 days.[1] 2018 EC4 has an absolute magnitude of 20.1 which gives a characteristic diameter of 300 m.[1]
Mars trojan and orbital evolution
Recent calculations indicate that it is a stable L5 Mars trojan with a libration period of 1250 yr and an amplitude of 17°.[2] These values are similar to those of 5261 Eureka and related objects and it may be a member of the so-called Eureka family.[citation needed]
Mars trojan
L4 (leading):
L5 (trailing):
- 5261 Eureka (1990 MB) †
- (101429) 1998 VF31 †
- (311999) 2007 NS2 †
- (385250) 2001 DH47
- 2009 SE
- 2011 SC191
- 2011 SL25
- 2011 SP189
- 2011 UB256
- 2011 UN63
- 2016 CP31
- 2018 EC4
- 2018 FC4
See also
References
- ↑ 1.0 1.1 1.2 "JPL Small-Body Database Browser: (2018 EC4)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2018EC4;cad=1.
- ↑ 2.0 2.1 de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (March 2021). "Using Mars co-orbitals to estimate the importance of rotation-induced YORP break-up events in Earth co-orbital space". Monthly Notices of the Royal Astronomical Society 501 (4): 6007–6025. doi:10.1093/mnras/stab062. Bibcode: 2021MNRAS.501.6007D. https://academic.oup.com/mnras/article-abstract/501/4/6007/6081058.
- ↑ 3.0 3.1 MPC data on 2018 EC4
Further reading
- Three new stable L5 Mars Trojans de la Fuente Marcos, C., de la Fuente Marcos, R. 2013, Monthly Notices of the Royal Astronomical Society: Letters, Vol. 432, Issue 1, pp. 31–35.
- Orbital clustering of Martian Trojans: An asteroid family in the inner solar system? Christou, A. A. 2013, Icarus, Vol. 224, Issue 1, pp. 144–153.
External links
- 2018 EC4 data at MPC.
- 2018 EC4 at AstDyS-2, Asteroids—Dynamic Site
- 2018 EC4 at the JPL Small-Body Database
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