Using data from NASA’s Kepler mission, a team of astronomers led by Carnegie Institution scientist Dr Brian Jackson has found 13 extrasolar planets with very short orbital periods and so close to their parent stars that they are nearly skimming the stellar surface.

Most gas giant exoplanets with orbital periods less than or equal to a few days are unstable. This is due to decay in their orbits caused by the effects of their star’s proximity.

For rocky or icy planets, this disruption could bring them close enough to the star that the force of their own gravity can no longer hold them together in the face of the star’s gravity.

Motivated by these considerations, Dr Jackson and his colleagues searched for very short-period transiting objects in the publicly available Kepler dataset.

Their survey, reported in a paper submitted for publication in the Astrophysical Journal (arXiv.org), revealed 13 planetary candidates, all with periods ranging from 3.3 to 10 hours.

Even with masses of only a few times that of Earth, the short periods mean they might be detectable by currently operating ground-based facilities.

If confirmed, these planets would be among the shortest-period planets ever discovered.

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Bibliographic information: Brian K. Jackson et al. A Survey for Very Short-Period Planets in the Kepler Data. Submitted to ApJ; arXiv: 1308.1379