(419624) 2010 SO 16

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Asteroid
2010 SO 16
Properties of the orbit ( animation )
Orbit type Near-Earth asteroid , Apollo-type
horseshoe orbit to Earth
Major semi-axis 1.001  AU
eccentricity 0.0752
Perihelion - aphelion 0.926 AU - 1.076 AU
Inclination of the orbit plane 14.5 °
Length of the ascending node 40.5 °
Argument of the periapsis 108 °
Time of passage of the perihelion March 5, 2010
Sidereal period 1.00 a
Physical Properties
Medium diameter 200-400 m
Absolute brightness 20.6 mag
history
Explorer WISE space telescope
Date of discovery 17th September 2010
Another name MPO192619
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.

(419624) 2010 SO 16 is an Apollo-type asteroid discovered in 2010 with the help of the WISE space telescope. Its inclination is 14.5 °, the absolute brightness 20.6. With a diameter of about 300 meters it is the largest known asteroid on a terrestrial horseshoe orbit runs, and overall the fourth Anm1 been discovered object of this type.

Special features of the railway

Schematic representation of a horseshoe track with earth, sun and the Lagrangian points L 1 to L 5

Due to its special orbit shape, SO 16 has practically the same distance to the sun in 2010 as the earth itself. It comes close to the earth to a maximum of 20 million km. This corresponds to about 50 times the distance to the moon, which is why there is no risk of collision. The opening angle 2 φ min , i.e. the gap in the horseshoe in which the earth is located, is 25 °. The duration of the cycle on the horseshoe is 350 years.

Track shape

Orbits of earth (white, earth itself green), (419624) 2010 SO 16 (blue) as well as the positions of the sun, Mercury and Venus on September 17, 2010; above vertical view of the ecliptic, below horizontal view

Based on the existing path data were computer simulations performed possible paths. The eight main planets were also taken into account. The gravitational effect of the moon was taken into account as an additional earth mass. The calculations were made using the Radau method . Two calculations were made:

  • The first was based on observations from WISE and ground-based telescopes, including Spacewatch II , over 62 days up to November 18, 2010,
  • the second based on additional observations from Spacewatch II over 75 days until December 1, 2010.

Both simulations resulted in a horseshoe orbit. At the time of April 2011 the asteroid was near the turning point, which is behind the earth. By 2016, SO 16 will come close to Earth between 0.13 and 0.2 AU in 2010 . It will be observable in the evening sky for several decades.

A series of path variants was dynamically integrated to check the simulations. The calculations were also used to study the length of time the asteroid stayed on the horseshoe track. The following parameters were varied:

For a nine values ​​were calculated in the range of the measurement inaccuracy 1- σ , for the other parameters three values ​​each in the range 1.5- σ , so a total of 9 × 3 3  = 243 path variants. The calculations were carried out for a period of ± 100,000 years based on the present. In all cases there were horseshoes.

stability

In order to investigate the stability of the horseshoe train, further train variants were calculated. The major semi-axis was varied in the range of ± 4 σ . 35 variants each were calculated for the past and the future; So a total of 70 track variants. The integrations were calculated up to a period of 2 million years. The results of these calculations are shown in Table 1.

Table 1 - Number of lanes found depending on the length of stay
Length of stay
in years		 number Remarks
<200,000 4th Shortest established residence time 120,000 years
200,000-500,000 50
> 500,000 16 Of which 8> 1 million years and 2> 2 million years (end of integration)

This means that the 2010 SO 16 runway is far more stable than other objects on similar runways that leave their horseshoe tracks after a few thousand years.

The asteroid has accompanied the earth for at least 250,000 years, and its origin may even go back to the early days of our solar system.

origin

Three possible origins were discussed. An origin from the main belt is considered unlikely because of the earth-like orbit, but it cannot be completely ruled out. The origin from the earth-moon system is just as unlikely, since the orbit would change several times within a few 100,000 years.

A third possibility is the origin on a kidney-shaped orbit near the L 4 or L 5 Lagrangian points of the asteroid-earth-sun system. SA Tabachnik and NW Evans showed in a publication in 2000 that objects on such orbits can survive 50 million years, provided the inclination i and eccentricity e have the correct values ​​(for i : either 24 ° < i <34 ° or i < 16 °; for e : e ≈ 0.06). In the case of 2010 SO 16 , both sizes are in the appropriate ranges. Extrapolations over 5 billion years also showed that a small part of the asteroids could survive even such long periods on corresponding orbits.

On the other hand, it can be argued that the calculations by Tabachnik and Evans ignore the Jarkowski effect . 2010 SO 16 could hardly last longer than a few million years on a corresponding runway. However, a study on the stability of Mars Trojans in 2005 showed that the Jarkowski Effect does not necessarily destabilize large Trojans.

For a final decision, more information about size, spectral class and angular momentum would be necessary. 2010 SO 16 could also be a test object for the verification of the Jarkowski acceleration.

Web links

Remarks

Note 1The previously discovered asteroids are 2001 GO 2 , 2002 AA 29 and (54509) YORP . This also corresponds to the number mentioned in the report by Rüdiger Vaas on Wissenschaft.de and in the text of the article by Christou and Asher. Other lists, however, contain another object: (3753) Cruithne . It should be noted that (3753) Cruithne has a path shape that differs very strongly from the horseshoe path, which actually corresponds to a kidney-shaped path.

Individual evidence

  1. ↑ a b c d e f g AA Christou, DJ Asher : A long ‐ lived horseshoe companion to the Earth . In: Monthly Notices of the Royal Astronomical Society . tape 414 , no. 4 , 2011, p. 2965–2969 , doi : 10.1111 / j.1365-2966.2011.18595.x ( academic.oup.com [PDF; 2.1 MB ]).
  2. ↑ a b c Rüdiger Vaas: Secret companion of the earth. In: Wissenschaft.de. April 7, 2011, accessed September 9, 2019 .
  3. ↑ Apostolos Christou, David Asher: (419624) 2010 SO16 in the Small-Body Database of the Jet Propulsion Laboratory (English).Template: JPL Small-Body Database Browser / Maintenance / Alt
  4. ↑ Asteroid 2010 SO16 is following Earth in its orbit around sun . EarthSky, April 6, 2011.
  5. ↑ Asteroid Stalks Earth in Weird Horseshoe-Shaped Orbit . SPACE.com, April 6, 2011.
  6. ↑ Astronomers Find Newly Discovered Asteroid is Earth's Companion ( Memento from May 14, 2011 in the Internet Archive ). Armagh Observatory, accessed April 30, 2011.
  7. ^ SA Tabachnik, NW Evans: Asteroids in the inner solar system - I. Existence . In: Monthly Notices of the Royal Astronomical Society . tape 319 , no. 1 , 2002, p. 63-79 , doi : 10.1046 / j.1365-8711.2000.03760.x .
  8. ^ H. Scholl, F. Marzari, P. Tricarico: Dynamics of Mars Trojans . In: Icarus . tape 175 , no. 2 , 2005, p. 397-408 , doi : 10.1016 / j.icarus.2005.01.018 .