One of the nearest stars to the Sun; a dwarf K star, somewhat cooler than and about one-seventh as luminous as the Sun, it lies in the constellation Indus. Around it, at an average distance of 1.46 AU (220 million km), orbits the nearest known brown dwarf. Discovered in 2003, this brown dwarf, Epsilon Indi Ba, has a mass of 40 to 60 times the mass of Jupiter and a surface temperature of about 1,260 K. Shortly after its discovery, Epsilon India Ba was found to have an orbital companion of its own – a cooler, fainter brown dwarf known as Epsilon Indi Bb. The projected separation as seen on the sky between Epsilon Indi and Indi Ba is approximately 1500 AU (one AU, or astronomical unit, is the average distance between the Earth and the Sun or about 93 million miles/150 million km), and the distance between Epsilon Indi Ba and the newly discovered Epsilon Indi Bb is at least 2.2 AU. Epsilon Indi Ba and Bb are members of a recently discovered type of astronomical object – the "T" class brown dwarfs.
Epsilon Indi has the tenth highest proper motion of any known star.
