ChaHα8 (also written ChaHa8 when
Greek letters
The Greek alphabet has been used to write the Greek language since the late 9th or early 8th century BC. It was derived from the earlier Phoenician alphabet, and is the earliest known alphabetic script to systematically write vowels as we ...
are unavailable) is a binary
brown dwarf
Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main sequence, main-sequence stars. Their mass is approximately 13 to 80 Jupiter mass, times that of Jupiter ()not big en ...
about from Earth in the constellation
Chamaeleon
Chamaeleon () is a small constellation in the deep southern sky. It is named after the chameleon, a kind of lizard. It was first defined in the 16th century.
History
Chamaeleon was one of twelve constellations created by Petrus Plancius f ...
. The designation indicates that it is in the
Chamaeleon I star-forming region and that it displays
hydrogen-alpha
Hydrogen-alpha, typically shortened to H-alpha or Hα, is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emit ...
emission. It was discovered in 2000.
[
It was found in 2007 to have a low-mass substellar companion in orbit around it via ]radial velocity
The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...
observations.[ The companion has a mass of 25–31 ]Jupiter mass
The Jupiter mass, also called Jovian mass, is the unit of mass equal to the total mass of the planet Jupiter. This value may refer to the mass of the planet alone, or the mass of the entire Jovian system to include the moons of Jupiter. Jupiter ...
es, and the pair orbit each other with a period of 5.2 years and an eccentricity of 0.59.[
]
References
External links
Video of the radial velocity orbit of the brown dwarf binary ChaHα8
Brown dwarfs
Binary stars
Chamaeleon
{{brown-dwarf-stub