2010 SO16
2010 SO16 is an asteroid from the Apollo - type, which was discovered in 2010 using the Space Telescope WISE. Its orbital inclination is 14.5 °, the absolute brightness of 20.6. With a diameter of about 300 meters it is the largest known asteroid, which runs on a ground-based horseshoe orbit, and overall the vierteAnm 1 so far discovered object of this type
Special features of the web
Due to its special web form 2010 SO16 practically the same distance from the sun as the earth itself has He comes to the earth to a maximum of 20 million kilometers near. This corresponds to about 50 times the lunar distance, and therefore no risk of collision. The opening angle 2φmin, thus the gap of the horse shoe, which is located in the ground is 25 °. The duration of the amount outstanding on the horseshoe railway is 350 years.
Web form
Based on the available data path computer simulations of possible lifts were performed. In this case, the eight major planets were taken into account. The gravitational effect of the moon was reflected as additional mass of the Earth. The calculations were made by means of wheel method. There are two calculations are performed:
- The first was based on the observations of WISE and ground-based telescopes, including Spacewatch II, about 62 days until 18 November 2010
- The second on additional observations of Spacewatch II over 75 days until 1 December 2010.
Both simulations a horseshoe orbit. At the time of April 2011, the asteroid was near the reversal point, which is located behind the Earth. Until 2016 2010 SO16 Earth from 0.13 to 0.2 AE will come close. It will be observable even for several decades in the evening sky.
To verify the simulations, a series of monorails was dynamically integrated. The calculations also served to examine the length of stay of the asteroid on the horseshoe orbit. The following parameters were varied here:
- Semi-major axis a
- Mean anomaly M
- Eccentricity e
- Ω argument of pericentre
For a nine values were calculated in the range of measuring accuracy 1- σ, for the remaining parameters, three values in the range 1.5 - σ, for a total of 9 × 33 = 243 monorails. The calculations were carried out with respect for a period of ± 100,000 years to the present. In all cases, horseshoe orbits revealed.
Stability
To investigate the stability of the shoe track, more monorails were calculated. The semi-major axis is in the range ± 4σ was varied. Were calculated per 35 variants for the past and the future; a total of 70 monorails. The integrations were calculated up to a period of 2 million years ago. The results of these calculations are shown in Table 1
Thus the orbit of 2010 SO16 is far more stable than the other objects on similar orbits, which leave their horseshoe track after a few thousand years.
The asteroid accompanied the earth for at least 250,000 years, possibly enough to be dating back even to the early days of our solar system.
Origin
Three possible origins are discussed. An origin from the main belt holds because the Earth-like orbit as unlikely, however, can not be completely ruled out. Equally unlikely is considered the origin of the Earth-Moon system, as the web would change several times within a few 100,000 years.
A third possibility is the origin on a kidney- shaped path near the Lagrange points L4 or L5 of the asteroid - Earth-Sun system. SA Tabachnik and NW Evans showed in a paper in 2000 that objects on such orbits can certainly last for 50 million years, assuming 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 SO16 are both sizes in the appropriate areas. Extrapolations about 5 billion years also revealed that a small part of the asteroid could survive such long periods on respective tracks themselves.
Contrast can be argued that the calculations of Tabachnik and Evans let the Yarkovsky effect into account. This results in near-Earth asteroids to accelerations of typically 10-9 AE per year. 2010 SO16 could survive on an appropriate path thus hardly more than a few million years. However, a study on the stability of Mars Trojans in 2005 has revealed that the Yarkovsky effect large Trojans do not necessarily destabilizing.
For a final decision more information on size, spectral and angular momentum would be necessary. 2010 SO16 could also be a test subject for the detection of the Yarkovsky acceleration here.