| Discovery | |
|---|---|
| Discovered by | Mt. Lemmon Survey |
| Discovery date | 21 March 2018 |
| Designations | |
| MPC designation | 2018 FC4 |
| Minor planet category | Martian L5  |
| Orbital characteristics | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 790 days (2.16 yr) |
| Aphelion | 1.5498684 AU (231.85701 Gm) |
| Perihelion | 1.497823 AU (224.0711 Gm) |
| Semi-major axis | 1.5238457 AU (227.96407 Gm) |
| Eccentricity | 0.017077 |
| Orbital period (sidereal) | 1.88 yr (687.0841 d) |
| Mean anomaly | 4.660° |
| Mean motion | 0° 31 26.232 /day |
| Inclination | 22.1437° |
| Longitude of ascending node | 187.55390° |
| Argument of perihelion | 52.009° |
| Earth MOID | 0.507683 AU (75.9483 Gm) |
| Jupiter MOID | 3.41333 AU (510.627 Gm) |
| Physical characteristics | |
| Dimensions | 200 m |
| Geometric albedo | 0.5-0.05 (assumed) |
| Absolute magnitude (H) | 21.3 |
2018 FC4 is a small asteroid and Mars trojan orbiting near the L5 point of Mars (60 degrees behind Mars on its orbit).
Discovery, orbit and physical properties
2018 FC4 was first observed on 21 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 the previous night. Its orbit is characterized by very low eccentricity (0.017), moderate inclination (22.1°) and a semi-major axis of 1.52 AU. Upon discovery, it was classified as Mars-crosser by the Minor Planet Center. Its orbit is reasonably well determined as it is currently (January 2021) based on 35 observations with a data-arc span of 790 days. 2018 FC4 has an absolute magnitude of 21.3 which gives a characteristic diameter of 200 m.
Mars trojan and orbital evolution
Recent calculations indicate that it is a stable L5 Mars trojan with a libration period of 1300 yr and an amplitude of 20°. These values are similar to those of 5261 Eureka and related objects and it may be a member of the so-called Eureka family.
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
- ^ "JPL Small-Body Database Browser: (2018 FC4)". Jet Propulsion Laboratory. Retrieved 12 January 2021.
- ^ 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. arXiv:2101.02563. Bibcode:2021MNRAS.501.6007D. doi:10.1093/mnras/stab062.
- ^ MPC data on 2018 FC4
- 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 FC4 data at MPC.
- 2018 FC4 at AstDyS-2, Asteroids—Dynamic Site
- 2018 FC4 at the JPL Small-Body Database
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