| 词条 | (311999) 2007 NS2 |
| 释义 |
|minorplanet = yes |name = {{mp|(311999) 2007 NS|2}} |background = #FA8072 |image = |caption = |discovery_ref = [1] |discoverer = |discovered = 14 July 2007 |discovery_site= Observatorio Astronómico de La Sagra |mpc_name = |mp_category = {{mpcat|Martian L5|125}} |alt_names = |orbit_ref = [2][3] |epoch = 13 January 2016 (JD 2457400.5) |aphelion = {{Convert|1.6061055|AU|Gm|abbr=on|lk=on}} |perihelion = {{Convert|1.4414495|AU|Gm|abbr=on}} |semimajor = {{Convert|1.5237775|AU|Gm|abbr=on}} |eccentricity = 0.0540289 |period = 1.88 yr (687.04 d) |inclination = 18.62037° |asc_node = 282.49476° |mean_anomaly = 29.476921° |arg_peri = 176.94930° |satellites = |dimensions = 800–1600 m |mass = |density = |sidereal_day = |albedo = |spectral_type = |abs_magnitude = 18.1 |mean_motion = 0.5239885°/day |observation_arc= 6296 days (17.24 yr) |uncertainty = 0 }} {{mp|(311999) 2007 NS|2}} is an asteroid and Mars trojan orbiting near the {{L5|pt=yes}} of Mars. Discovery, orbit and physical properties{{mp|(311999) 2007 NS|2}} 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] {{mp|2007 NS|2}} has an absolute magnitude of 17.8, which gives a characteristic diameter of 870 m.[2] Mars trojan and orbital evolutionJean Meeus suspected that {{mp|(311999) 2007 NS|2}} 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]OriginLong-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 {{mp|(311999) 2007 NS|2}} 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
References1. ^ {{Cite news |date=July 16, 2007 |title=Major News About Minor Objects |url=http://www.hohmanntransfer.com/mn/07/07197_0716.htm |accessdate=April 22, 2009}} 2. ^1 2 {{cite sbdb|title=311999 (2007 NS2)|id=2311999|orbit=yes|access-date=28 March 2016}} 3. ^AstDys-1 4. ^2007 NS2 discovery blog 5. ^Discovery MPEC 6. ^Update MPEC 7. ^[https://www.newscientist.com/article/dn12331 New Scientist article on the discovery] 8. ^1 MPC data on 2007 NS2 9. ^{{cite web|url=http://britastro.org/asteroids/Asteroid%20news.htm |title=Table of contents |publisher=Britastro.org |date= |accessdate=2013-10-29}} 10. ^{{cite journal |last1=Schwarz |first1=R. |last2=Dvorak |first2=R. |year=2012 |title=Trojan capture by terrestrial planets |journal=Celestial Mechanics and Dynamical Astronomy |volume=113 |issue=1 |page=23 |bibcode=2012CeMDA.113...23S |doi=10.1007/s10569-012-9404-4|arxiv=1611.07413}} 11. ^1 2 {{cite journal |first=Carlos |last=de la Fuente Marcos |last2=de la Fuente Marcos |first2=Raúl |year=2013 |title=Three new stable L5 Mars Trojans |journal=Monthly Notices of the Royal Astronomical Society Letters |volume=432 |issue=1 |pages=L31–L35 |arxiv=1303.0124 |bibcode=2013MNRAS.432L..31D |doi=10.1093/mnrasl/slt028}} 12. ^{{cite journal |last1=Christou |first1=A. A. |year=2013 |title=Orbital clustering of Martian Trojans: An asteroid family in the inner solar system? |journal=Icarus |volume=224 |issue=1 |pages=144–153 |arxiv=1303.0420 |bibcode=2013Icar..224..144C |doi=10.1016/j.icarus.2013.02.013}}
|last1=Rodriguez |first1=J. |year=2007 |title=2007 NS2 |journal=Minor Planet Electronic Circular |bibcode=2007MPEC....O...03R |pages=2007-0303 |display-authors=etal}}
|last1=Skiff |first1=B. A. |year=2007 |title=2007 NS2 |journal=Minor Planet Electronic Circular |pages=2007-O09 |bibcode=2007MPEC....O...09S |display-authors=etal}}
|last1=Schwarz |first1=R. |last2=Dvorak |first2= R. |year=2007 |title=Trojan capture by terrestrial planets |journal=Celestial Mechanics and Dynamical Astronomy |volume=113 |issue=1 |page=23 |bibcode=2012CeMDA.113...23S |doi=10.1007/s10569-012-9404-4 |arxiv=1611.07413}}
|first=Carlos |last=de la Fuente Marcos |last2=de la Fuente Marcos |first2=Raúl |year=2013 |title=Three new stable L5 Mars Trojans |journal=Monthly Notices of the Royal Astronomical Society Letters |volume=432 |issue=1 |pages=L31 |arxiv=1303.0124 |bibcode=2013MNRAS.432L..31D |doi=10.1093/mnrasl/slt028 }}
|last1=Christou |first1=A. A. |year=2007 |title=Orbital clustering of martian Trojans: An asteroid family in the inner Solar System? |journal=Icarus |volume=224 |issue=1 |page=144 |arxiv=1303.0420 |bibcode=2013Icar..224..144C |doi=10.1016/j.icarus.2013.02.013 }} External links
4 : Mars trojans|Discoveries by OLS|Discoveries by the Observatorio Astronómico de Mallorca|Astronomical objects discovered in 2007 |
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