82 G. Eridani
82 G. Eridani (also: HD 20794 , HR 1008 or e Eridani ) is a star in the constellation Eridanus, about 20 light years away from Earth . It is a main sequence star with the star class G6 V, and in its orbit there are at least three planets and a dust disk.
Observation
In the southern celestial catalog Uranometria Argentina , 82 G. Eridani (sometimes abbreviated as 82 Eridani) is listed as the 82nd star in the constellation Eridanus. The Argentina catalog by astronomer Benjamin Apthorp Gould is a southern celestial hemisphere analogue of the better known Flamsteed catalog.
properties
82 G. Eridani is smaller and less massive than the sun , which means that its apparent brightness is lower compared to the sun. He seems more than a third brighter than Tau Ceti and Alpha Centauri B .
Planetary system
On August 17, 2011, European astronomers announced the discovery of three planets orbiting 82 G. Eridani. They classify the values of their masses as so-called " super-earths "; objects with a mass that is only a few times the mass of the earth . These three planets were only discovered through very precise measurements of the radial velocity of 82 G. Eridani, where gravitation orbital deflections were found, which provided evidence of the existence of the planets, and none of the planets exhibited any significant eccentricity in their respective orbit.
Life on 82 G. Eridani
In his book " Habitable Planets for Men " , published in 1970, Stephen Dole gave 82 G. Eridani the highest habitability in his estimation: 5.7%. Next to 82 G. Eridani he gave 4 other stars of this rating: Alpha Centauri B , 70 Ophiuchi A , Eta Cassiopeiae A and the Delta Pavonids .
82 G. Eridani (GJ 139) was selected by NASA as the Stage 1 target star for the Space Interferometry Mission (SIM), the task of which was to find planets of Earth-like size.
Individual evidence
- ^ Benjamin Apthorp Gould: Uranometria Argentina: Brightness and Position of Every Fixed Star, Down to the Seventh Magnitude, Within One Hundred Degrees of the South Pole . Observatorio Nacional Argentino, 1879 ( google.de [accessed on August 1, 2020]).
- ↑ Stephen H. Dole: Habitable Planets for Man . Blaisdell Publishing Company, 1964 ( google.de [accessed August 1, 2020]).
- ↑ SIM | Science Mission Directorate. Retrieved August 1, 2020 .