The first object was spotted by the Lincoln Near-Earth Asteroid Research (LINEAR) sky survey. This project was set up by the United States Air Force, NASA and MIT’s Lincoln Laboratory with the aim of discovering and tracking near-Earth asteroids and it has had much success over the years. Observations are carried out by a pair of Ground Based Electro-Optical Deep Space Surveillance (GEODESS) telescopes which are located in Socorro, New Mexico. On January 6 the telescopes achieved their latest success when they observed a new object in the asteroid belt which is a region of the solar system located between the orbits of Mars and Jupiter. This new object was named P/2010 A2 and its appearance has caused some excitement in the astronomical community.

While it is not uncommon that a new object should be identified in the asteroid belt the unusual thing about P/2010 A2 is its appearance. Generally asteroids have a relatively circular orbit and are not volatile in nature. These show up as a speck of light on pictures taken from telescopes. Comets on the other hand tend to have an elliptical orbit around the Sun and exhibit a visible tail due to the effects of solar radiation on their nuclei. These tend to have a fuzzy appearance in pictures. The mystery with P2010 A2 is that it exhibits the traits of both an asteroid and a comet. While it has an orbit which is consistent with an asteroid the picture taken of the object appeared fuzzy which gives it the appearance of a comet. This came as a surprise in that comets do not normally reside in the asteroid belt and scientist have been working to come up with an explanation of why this should be.

Initial observations indicated that the aphelion (furthest distance from the Sun) of the object is only 2.6 Astronomical Units (AU). This would mean that it remains within the warmer inner regions of the asteroid belt where ice is less likely to form. The frost line is located at 2.7 AU and it is beyond this that more volatile ices are expected to form which are typical of a comet. With ice probably not forming on its surface, this has led to the theory that the unusual appearance may be as a result of a recent asteroid collision which exposed ice that had been originally trapped beneath the surface of the object. Melting of this ice and the resulting gas and dust which would be released would help to explain the tail of the object.

If this explanation is indeed true then it would be the first confirmed collision event between two asteroids. Although a similar event has probably occurred in the past, this would be the first time observations of the phenomenon had been made. Monitoring of the object is expected to continue in the near future to try and establish more details. Specialists hope that either the Hubble or Spitzer Space Telescopes can be brought to bear on the puzzle although this has yet to be confirmed.

In future another space telescope which may view the object is the WISE Telescope. This was launched into space at the end of 2009 and only a few weeks after the lens cover was removed from the instrument it is already starting to produce results. The official start of the WISE mission to map the entire night sky was January 14. However in tests prior to this the telescope showed why it will be an important part of detecting near-Earth asteroids in future. Two days before the official mission was to begin it was reported that WISE had already sighted its first asteroid. The sighting was confirmed by the University of Hawaii’s 2.2m visible light telescope and the asteroid was named 2010 SB78. Initial estimates indicate that the asteroid is around 1 kilometer in diameter and is currently at a distance of 158 million kilometers from Earth. It is not considered that the orbit of the asteroid will bring it near to Earth and while it is not considered to be a danger it will continue to be monitored.

With two new objects being discovered in a relatively short time period it is to be hoped that the pace at which asteroids are detected will accelerate in the future. The work of the many existing projects which detect and track near-Earth objects will be enhanced by the capabilities of the WISE telescope and this should mean our knowledge of asteroids in the vicinity of Earth should be greatly increased in the coming years.