2M1207b

2M1207b

Size comparison of 2M1207b with Jupiter.
Discovery
Discovered by	Chauvin et al.
Discovery site	Paranal Observatory, Chile
Discovery date	April 2004
Detection method	Imaged
Orbital characteristics
Semi-major axis	24–231 AU (3.6×109–3.46×1010 km)[1]
Eccentricity	0.02–0.98[1]
Orbital period (sidereal)	633–20046[1] y
Inclination	13–150[1]
Longitude of ascending node	7–174[1]
Time of periastron	2107.69–12883.36[1]
Argument of periastron	4–176[1]
Star	2M1207
Physical characteristics
Mean radius	1.15 RJ[2]
Mass	5.5±0.5[3] MJ
Temperature	1200 K[3]
Spectral type	mid-to-late L[3]
Atmosphere
Composition by volume	hydrogen, water, carbon monoxide, helium[3][4]

2M1207b is a planetary-mass object orbiting the brown dwarf 2M1207, in the constellation Centaurus, approximately 170 light-years from Earth.^[5] It is one of the first candidate exoplanets to be directly observed (by infrared imaging). It was discovered in April 2004 by the Very Large Telescope (VLT) at the Paranal Observatory in Chile by a team from the European Southern Observatory led by Gaël Chauvin.^[6] It is believed to be from 5 to 6 times the mass of Jupiter^[3] and may orbit 2M1207 at a distance roughly as far from the brown dwarf as Pluto is from the Sun.^[7]

The object is a very hot gas giant; the estimated surface temperature is roughly 1200 K (930 °C or 1700 °F),^[3] mostly due to gravitational contraction.^[8] Its mass is well below the calculated limit for deuterium fusion in brown dwarfs, which is 13 Jupiter masses. The projected distance between 2M1207b and its primary is around 40 AU (similar to the mean distance between Pluto and the Sun).^[9] Its infrared spectrum indicates the presence of water molecules in its atmosphere.^[10][4] The object is not a likely candidate to support life, either on its surface or on any satellites.