HD 136118 b

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HD 136118 b
Exoplanet List of exoplanets
Parent star
Star HD 136118
Constellation Serpens
Right ascension (α) 15h 18m 55.4719s
Declination (δ) –01° 35′ 32.590″
Distance 171 ly
(52.3 pc)
Spectral type F9V
Orbital elements
Semi-major axis (a) 1.45 ± 0.25 AU
Periastron (q) 0.94 AU
Apastron (Q) 1.96 AU
Eccentricity (e) 0.352 ± 0.006
Orbital period (P) 1209 ± 24 d
(3.31 y)
Inclination (i) 163.1 ± 3°
Argument of
(ω) 316.4 ± 0.6°
Time of periastron (T0) 2450610.5 ± 3.7 JD
Physical characteristics
Mass (m) 42+11
Discovery information
Discovery date February 7, 2002
Discoverer(s) Fischer "et al."[1]
Discovery method Doppler Spectroscopy
Discovery site United States California
Discovery status Published[1]
Other designations
HIP 74948 b

HD 136118 b is a brown dwarf located approximately 171 light-years away in the constellation of Serpens Cauda. This object had a minimum mass of 11.9 times that of Jupiter. Due to its high mass the planet is likely to be very hot and possibly glowing faintly. The lower limit on its mass is only slightly less than the deuterium burning threshold that some astronomers use to distinguish between planets and brown dwarfs. Depending on the inclination of its orbit, the true mass could be above this limit. The orbit of the object is located at the average distance of 1.45 astronomical units from the parent star, taking 40 months to complete one eccentric orbit.

On November 25, 2009, its inclination was calculated to be 163.1° and its true mass 42 times that of Jupiter, classifying this as a brown dwarf.[2]


  1. ^ a b Fischer, Debra A.; et al. (2002). "Planetary Companions to HD 136118, HD 50554, and HD 106252". Publications of the Astronomical Society of the Pacific. 114 (795): 529–535. Bibcode:2002PASP..114..529F. doi:10.1086/341677. 
  2. ^ Martioli, E.; et al. (2010). "The Mass of the Candidate Exoplanet Companion to HD136118 from Hubble Space Telescope Astrometry and High-Precision Radial Velocities". The Astrophysical Journal. 708 (1): 625–634. arXiv:0911.4645Freely accessible. Bibcode:2010ApJ...708..625M. doi:10.1088/0004-637X/708/1/625. 

External links[edit]

Coordinates: Sky map 15h 18m 55.4719s, −01° 35′ 32.590″