American astronomers have discovered the first candidates for exo-comets - comets outside the solar system. A related study is available at arXiv.org for publication in the Monthly Notices of the Royal Astronomical Society, briefly reported by New Scientist.
Potential exocomets have been discovered near the stars KIC 3542116 and KIC 11084727, located about 800 light years from the Sun. The objects were discovered using the Kepler space telescope, which allows one to detect exoplanets by the transit method (by the change in the luminosity of a star as it passes through the planet's disk).
As a rule, if a planet passes along the disk of a star, the graph of the change in luminosity has a symmetrical form. In the case of KIC 3542116 and KIC 11084727, the dependence had an asymmetric shape, which scientists associate with clouds of gas and dust from cometary tails.
In total, scientists admit the presence of from two to six comets near KIC 3542116, the number of objects around KIC 11084727 is more difficult to estimate (only one transit was observed), probably all of them are short-period - they complete a revolution around the star in less than three months.