HD 187123 b

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HD 187123 b
Exoplanet List of exoplanets
Parent star
Star HD 187123
Constellation Cygnus
Right ascension (α) 19h 46m 58.1130s
Declination (δ) +34° 25′ 10.288″
Distance 156.28 ly
(47.92 pc)
Spectral type G5V
Orbital elements
Semi-major axis (a) 0.0426 AU
Periastron (q) 0.0411 AU
Apastron (Q) 0.0441 AU
Eccentricity (e) 0.035 ± 0.015
Orbital period (P) 3.097 d
(0.008479 y)
Orbital speed (υ) 150 km/s
Argument of
(ω) 20°
Time of periastron (T0) 2,451,029.73 JD
Semi-amplitude (K) 70.6 m/s
Physical characteristics
Mass (m) >0.52 MJ
Discovery information
Discovery date 9 September 1998
Discoverer(s) Butler, Marcy,
Vogt, Apps et al.
Discovery method radial velocity
Discovery site California, United States
Discovery status Published

HD 187123 b is a typical "hot Jupiter" located approximately 156 light-years away in the constellation of Cygnus, orbiting the star HD 187123. It has a mass about half that of Jupiter and it orbits in a very tight, round orbit around the star every three days.[1][2]

The star has also been monitored for possible transits by the planet, but none was found.

See also[edit]


  1. ^ Butler, R. Paul; et al. (1998). "A Planet with a 3.1 Day Period around a Solar Twin". Publications of the Astronomical Society of the Pacific. 110 (754): 1389–1393. Bibcode:1998PASP..110.1389B. doi:10.1086/316287. 
  2. ^ Wright, J. T.; et al. (2009). "Ten New and Updated Multi-planet Systems, and a Survey of Exoplanetary Systems". The Astrophysical Journal. 693 (2): 1084–1099. Bibcode:2009ApJ...693.1084W. arXiv:0812.1582Freely accessible. doi:10.1088/0004-637X/693/2/1084. 

External links[edit]

Coordinates: Sky map 19h 46m 58.1130s, +34° 25′ 10.288″