Sunday 14 July 2013

An Earth-mass planet in an eight hour orbit.

The Kepler Space Telescope has discovered a large number of planets with orbits of only a few days, mostly in the 'Hot Jupiter' class of objects, which have masses equal to or greater than that of Jupiter and orbit close to their stars, a class of objects that astronomers had not predicted prior to their discovery. As the project has built up more data the presence of smaller planets in short orbits has also been revealed. As part of a project to examine exoplanets in the Kepler Field of View with the shortest orbital periods, a team of scientists led by Roberto Sanchis-Ojeda of the Department of Physics, and Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology, describe an Earth-mass planet in an eight hour orbit about a G-type yellow dwarf star, the shortest known orbit of a confirmed planet, in a paper published on the arXiv online database at Cornell University Library on 17 May 2013.

The planet in question orbits the star KIC 8435766, which has approximately 84% of the Sun's mass, and an effective surface temperature of ~5143 K (compared to 5778 K for our Sun). The planet is named KIC 8435766b, and has approximately 1.1 times the mass of the Earth. It orbits the star once every eight and a half hours, and is estimated to have a surface temperature of 2300-3100 K.

An artists impression of a rocky planet close to a yellow star. Darke Max Macedo.

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