Epsilon Indi

Epsilon Indi ( ε ​​Indi ) is a star system in the constellation Indus ( Indian ). He is a star of the southern sky and can only south of the 33rd parallel of north latitude are observed. In an apparent magnitude of 4.69 like the star is still just freiäugig to detect.

By far the brightest and only known up to 2002 Epsilon Indi A component belongs to the spectral class K4 -5V. Its age is estimated at 1.3 billion years. He has a comparable size with the sun, but colder.

Seen from Epsilon Indi from the sun is a star second size class in the constellation Ursa Major.

Proper motion

Epsilon Indi is only 11.8 light years away from us and, after Barnard's Star and Kapteyn's Star of the fixed stars with the third largest proper motion. Its proper motion in the night sky is 4.7 arc seconds per year - the equivalent of about one lunar diameter in 400 years. In about 1000 years, the star system will change over into the neighboring constellation Toucan.

Companion of Epsilon Indi

In the years 2002 and 2003 Epsilon Indi was recognized as a star system. In the search for planets outside our solar system astronomers found two mutually orbiting brown dwarfs in 1200 astronomical units distance from Epsilon Indi A. 2002, slightly lighter Epsilon Indi B was found a brown dwarf of spectral type T1 with a surface temperature of 1200 K and a mass of about 50 Jupiter masses. A year later, the weaker luminous brown dwarf Epsilon Indi C was found, belonging to the spectral class T6, has a surface temperature of 850 K and a mass of about 30 Jupiter masses. The distance between the two components B (Ba ) and C ( Bb ) is about 2.1 AU; both have a diameter which approximately corresponds to the planet Jupiter. Currently ( 2007) it is in these two objects are the closest to the Sun previously discovered brown dwarfs.