2011 HM 102

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Asteroid
2011 HM 102
Properties of the orbit ( animation )
Orbit type Neptune Trojan (L 5 )
Major semi-axis 30.0  AU
eccentricity 0.08
Perihelion - aphelion 27.7 AU - 32.4 AU
Inclination of the orbit plane 29.4 °
Sidereal period 165 a
Physical Properties
Medium diameter 90 to 180 km
Absolute brightness 8.1 likes
history
Explorer Alex H. Parker et al. a.
Date of discovery April 29, 2011
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items.

The asteroid 2011 HM 102 is the ninth confirmed Neptune Trojans of the planet Neptune . This is the name of asteroids that orbit the sun on the Lagrange points of Neptune's orbit. 2011 HM 102 is also the third Trojan to be assigned to the Lagrange point L 5 . In this position he follows Neptune by 60 °.

Discovery and naming

2011 HM 102 was discovered on April 29, 2011 as part of the "New Horizons KBO Search Survey" program to find Trans-Neptunian objects as possible targets for a passage to a more distant Kuiper belt object after the New Horizons space probe had passed the Pluto system in the Discovered July 2015. The discovery of another L 5 Neptune Trojan was therefore rather accidental. The first image of the asteroid was taken on April 29, 2011 and the discovery was announced on October 8, 2012.

properties

The Trojan has been observed since its discovery from April 29, 2011 to April 17, 2012, a total of 145 times so far, which resulted in an observation sheet of 354 days (as of Feb. 2014).

2011 HM 102 orbits the sun on a prograde , moderately elliptical orbit between 27.7 AU and 32.4 AU distance. The orbit eccentricity is 0.08, the orbit is inclined 29.4 ° with respect to the ecliptic . The orbit period of 2011 HM 102 is 165 years.

2011 HM 102 has the most inclined orbit of all known Neptune Trojans. Even with the Jupiter Trojans, only 5% have a higher orbit inclination . According to calculations, the asteroid's orbit should remain stable for another million years.

The diameter of 2011 HM 102 is estimated to be around 90 to 180 kilometers, depending on the asteroid's as yet unknown albedo . With an absolute brightness of 8.1 mag, it is so far the brightest L 5 Trojan in the solar system . It is at least as bright or slightly brighter than (617) Patroclus , who, however, forms a binary system with his moon Menoetius . If 2011 HM 102 is actually a single object and its albedo is similar to the Patroclus-Menoetius system, that makes it the largest L 5 trojan in the solar system.

It has a rounded shape and is similar in color to the previously discovered L 4 Trojans of Neptune; this suggests that the Trojans have a similar composition on both Lagrangian points .

New Horizons flyby

2011 HM 102 is the first trans-Neptunian object that could have been observed by the New Horizons spacecraft launched in 2006 by means of a distant flyby. At the end of 2013, the probe approached the Trojan to around 1.2 AU (180 million km) - 2011 HM 102 was the closest known celestial body to the probe at that time. Despite the distance, the Trojan might have been bright enough to be picked up by one of New Horizons' cameras, but that wasn't enough for meaningful observation. Finally, no observation was made. The probe passed on 25/26. August 2014 the Neptune Railway.

See also

Web links

Individual evidence

  1. Alex H. Parker: Discovery
  2. 2011 HM 102 at JPL