Epsilon Eridani b

Epsilon Eridani b is an extrasolar planet orbiting the main sequence star Epsilon Eridani. Due to its high mass is assumed that it is a gas planet. Epsilon Eridani b is the Earth nearest extrasolar planet which previously could be detected. He is little more than ten light years away.

Discovery

Since Epsilon Eridani is one of the next of Sun-like stars, has been an intensive search for orbiting planets. The strong activity and variability of the star made ​​it difficult to locate using the methods of radial velocity. It has been argued that the star activity can also simulate the presence of planets. In addition, the low metallicity of the system decreases ( about half of the solar system ) the chance of planet formation.

In the early 1990s, the existence of satellites by a Canadian team led by Bruce Campbell and Gordon Walker, accepted. However, their observations were not substantiated enough to prove his existence with it.

Finally, in 2000 was formally the discovery of the planet Epsilon Eridani b by a team led by Artie Hatzes announced. The discoverers particular its mass as 1.2 ± 0:33 times the mass of the planet Jupiter.

Other researchers ( Geoffrey Marcy ) demanded more information about the Doppler effect of the star, which is caused by its large and varying magnetic field. The discovery was initially controversial. Finally, additional observations from the Hubble Space Telescope, which increased the observation time in nearly 15 years have confirmed the existence of exoplanets. In early October 2006, this was published by Fritz Benedict of the University of Texas in Austin and his staff.

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Epsilon Eridani b orbits Epsilon Eridani with a period of 6.85 years at an average distance of 3.39 AU, the orbit after the final calculation should have an eccentricity of 0.7, which would be one of the largest values ​​among the known exoplanets. He would thus classified as " Eccentric Jupiter". Its orbital plane is inclined at 30.1 degrees to the line of sight - and agrees so exactly with the inclination of the gas and dust disk around the star match. The last Apastron he reached in September 2010. A round lasts 2502 Earth days, nearly seven years.

Physical Properties

Since the angle of inclination of the orbital plane and the radial velocity variation of the host star are known, the mass of Epsilon Eridani b to approximately 492.7 Earth masses and 1.55 Jupiter masses can be determined. It is a gas giant with very high probability, and consists mainly of light elements such as hydrogen and helium. If confirmed, the high eccentricity, Epsilon Eridani b sharp fluctuations in insolation would be exposed. As a young planet it should form no ammonia clouds, its upper atmosphere is probably influenced by water clouds.