CoRoT-7 b

, Formerly called CoRoT -7 b, CoRoT - Exo - 7b, is the name of an exoplanet in the constellation of Monoceros. With a diameter of about 22,000 kilometers, it is one of the smallest known exoplanets. He was discovered in January 2009, accompanied the star CoRoT -7 and is about 150 parsecs ( about 490 light years) from Earth.

Properties

CoRoT -7 b has a diameter of about 22,000 kilometers ( about 3.6 Earth radii or 1.8 times the diameter of Earth, about 0.31 Jupiter radii ) and was discovered in January 2009 as the seventh candidate exoplanets using the CoRoT space telescope, which his name came about. Exoplanets are due to the large number of newly discovered extrasolar planets with the name of the central star supplemented by an additional small letters ( in the Roman alphabet beginning with " b") identified. In this case produces the usual designation of the central star from the discovered exoplanets stirred in him.

The planet is from Earth about 150 parsecs ( about 490 light-years ) away and accompanies its host star CoRoT -7 at a distance of about 2.55 million km (about 0,017 AE). For one orbit around its star of the exoplanet requires only about 20 hours.

After the mass of CoRoT -7 b initially to about 11 Earth masses (about 0,035 MJ) was estimated, provided more accurate measurements ( with the participation of the Thuringian State Observatory ), taking account of the newly discovered planetary neighbor CoRoT -7 c that CoRoT -7 b with 4.8 earth masses of the lowest mass ever exoplanets found so far is. Since the diameter of CoRoT -7 b is relatively small, it is counted among the terrestrial planets and the so-called super-Earths. Due to the Earth-like density of a rocky planet is assumed.

The surface temperature is estimated due to the small distance to the central star over 1300 Kelvin (~ 1000 ° C). The atmosphere consists, according to a simulation of the Washington University in St. Louis, especially of sodium, potassium, silicon monoxide and oxygen. A lower proportion of ingredients make the vaporized by the intense heat rock: magnesium, aluminum, calcium and iron. It is believed that these substances condense into higher layers of the atmosphere and on CoRoT -7b therefore pebbles " raining".

The central star

→ Main article: CoRoT -7

The star CoRoT -7 is a main sequence star of spectral type K0 with an apparent magnitude of 11.7 mag. With a surface temperature of about 5300 Kelvin, it is similar to the sun.