2018 EC₄

2018 EC₄
Discovery
Discovered by	Mt. Lemmon Survey
Discovery date	10 March 2018
Designations
MPC designation	2018 EC4
Minor planet category	Martian L5
Orbital characteristics
	Epoch 31 May 2020 (JD 2459000.5)
	Uncertainty parameter 0
Observation arc	3131 days (8.57 yr)
Aphelion	1.61579336 AU (241.719246 Gm)
Perihelion	1.43135923 AU (214.128293 Gm)
Semi-major axis	1.52357630 AU (227.923770 Gm)
Eccentricity	0.06052671
Orbital period (sidereal)	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°
Argument of perihelion	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[edit]

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[edit]

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[edit]

L₄ (leading):

(121514) 1999 UJ7 †

L₅ (trailing):

References[edit]

^ ^a ^b ^c "JPL Small-Body Database Browser: (2018 EC4)". Jet Propulsion Laboratory. Retrieved 12 January 2021.
^ ^a ^b 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.
^ ^a ^b MPC data on 2018 EC4

External links[edit]

2018 EC₄ data at MPC.
2018 EC4 at AstDyS-2, Asteroids—Dynamic Site
- Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
2018 EC4 at the JPL Small-Body Database
- Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

[jpl-1] "JPL Small-Body Database Browser: (2018 EC4)". Jet Propulsion Laboratory. Retrieved 12 January 2021.

[dynamics-2] 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-3] MPC data on 2018 EC4

[1]

[2]

[3]