(311999) 2007 NS2

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2007 NS2
Discovery site Observatorio Astronómico de La Sagra
Discovery date 14 July 2007
Martian L5 Martian L5
Orbital characteristics[2][3]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc 6296 days (17.24 yr)
Aphelion 1.6061055 AU (240.26996 Gm)
Perihelion 1.4414495 AU (215.63778 Gm)
1.5237775 AU (227.95387 Gm)
Eccentricity 0.0540289
1.88 yr (687.04 d)
Inclination 18.62037°
Earth MOID 0.458159 AU (68.5396 Gm)
Jupiter MOID 3.51815 AU (526.308 Gm)
Physical characteristics
Dimensions 800–1600 m

(311999) 2007 NS2 is an asteroid orbiting near the L5 point of Mars.

Discovery, orbit and physical properties

(311999) 2007 NS2 was discovered on July 14, 2007, by the Observatorio Astronómico de La Sagra.[4][5][6][7][8] Its orbit is characterized by low eccentricity (0.054), moderate inclination (18.6°) and a semi-major axis of 1.52 AU.[8] Upon discovery, it was classified as Mars-crosser by the Minor Planet Center. Its orbit is well determined as it is currently (March 2013) based on 87 observations with a data-arc span of 4,800 days.[2] 2007 NS2 has an absolute magnitude of 17.8, which gives a characteristic diameter of 870 m.[2]

Mars trojan and orbital evolution

Jean Meeus suspected that (311999) 2007 NS2 was a Mars Trojan, and this was confirmed by Reiner Stoss’s analysis of two sets of observations dating from 1998 on the MPC database.[9] It was confirmed to be a Mars Trojan numerically in 2012.[10] Recent calculations confirm that it is a stable L5 Mars Trojan asteroid with a libration period of 1310 years and an amplitude of 14°.[11][12] These values as well as its short-term orbital evolution are similar to those of 5261 Eureka. Out of all known Mars Trojans, it currently has the smallest relative (to Mars) semimajor axis, 0.000059 AU.[11]


Long-term numerical integrations show that its orbit is very stable on Gyr time-scales (1 Gyr = 1 billion years). As in the case of Eureka, calculations in both directions of time (4.5 Gyr into the past and 4.5 Gyr into the future) indicate that (311999) 2007 NS2 may be a primordial object, perhaps a survivor of the planetesimal population that formed in the terrestrial planets region early in the history of the Solar System.[11]

See also


  1. "Major News About Minor Objects". July 16, 2007. Retrieved April 22, 2009.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  2. 2.0 2.1 2.2 "311999 (2007 NS2) orbit diagram". JPL Small-Body Database. Jet Propulsion Laboratory. SPK-ID: 2311999. Retrieved 28 March 2016.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  3. AstDys-1
  4. 2007 NS2 discovery blog
  5. Discovery MPEC
  6. Update MPEC
  7. New Scientist article on the discovery
  8. 8.0 8.1 MPC data on 2007 NS2
  9. "Table of contents". Britastro.org. Retrieved 2013-10-29.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  10. Schwarz, R.; Dvorak, R. (2012). "Trojan capture by terrestrial planets". Celestial Mechanics and Dynamical Astronomy. 113 (1): 23. Bibcode:2012CeMDA.113...23S. doi:10.1007/s10569-012-9404-4.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  11. 11.0 11.1 11.2 de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (2013). "Three new stable L5 Mars Trojans". Monthly Notices of the Royal Astronomical Society Letters. 432 (1): L31–L35. arXiv:1303.0124. Bibcode:2013MNRAS.432L..31D. doi:10.1093/mnrasl/slt028.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  12. Christou, A. A. (2013). "Orbital clustering of Martian Trojans: An asteroid family in the inner solar system?". Icarus. 224 (1): 144–153. arXiv:1303.0420. Bibcode:2013Icar..224..144C. doi:10.1016/j.icarus.2013.02.013.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
Further reading

External links