| Extrasolar planet | List of extrasolar planets | |
|---|---|---|
| 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 | ||
| Semimajor 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 periastron |
(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. |
|
| Detection method | radial velocity | |
| Discovery site | California, USA | |
| 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. However, there is a very slight possibility that the signal, thought to be caused by the planet, may be from starspots and stellar pulsations instead.[1][2]
The star has also been monitored for possible transits by the planet, but none was found.