Gamma Cephei Ab
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| Extrasolar planet | Lists of extrasolar planets | |
|---|---|---|
| Parent star | ||
| Star | Gamma Cephei A | |
| Constellation | Cepheus | |
| Right ascension | (α) | 23h 39m 20.8s |
| Declination | (δ) | +77° 37′ 56″ |
| Spectral type | K1IVe | |
| Orbital elements | ||
| Semimajor axis | (a) | 2.03 AU |
| Eccentricity | (e) | 0.2 ± 0.069 |
| Orbital period | (P) | 902.96 ± 6 d (2.47 y) |
| Inclination | (i) | ?° |
| Longitude of periastron |
(ω) | 75.6 ± 18.8° |
| Time of periastron | (τ) | 2,453,156.8 ± 52.4 JD |
| Physical characteristics | ||
| Mass | (m) | >1.59 MJ |
| Radius | (r) | ~1.03 RJ |
| Density | (ρ) | ? kg/m3 |
| Temperature | (T) | 322 K |
| Discovery information | ||
| Discovery date | 1989-2002 | |
| Discoverer(s) | Lawton, Wright et al. | |
| Detection method | Doppler Spectroscopy | |
| Discovery status | Confirmed | |
Gamma Cephei Ab is an extrasolar planet orbiting Gamma Cephei A every two years.
Contents |
[edit] Discovery
In 1989, the planet was announced by Anthony Lawton and P. Wright. This would have been the first confirmed extrasolar planet, and it was hypothesized based on the same radial velocity technique later used successfully by others. However, the claim was retracted in 1992 due to the quality of the data not being good enough to make a solid discovery.
But on September 24, 2002, Gamma Cephei Ab was final confirmed. The team of astronomers (including William D. Cochran, Artie P. Hatzes... etc.) at the Planetary Systems and their Formation Workshop announced the preliminary confirmation of a long-suspected planet Gamma Cephei Ab with a minimum mass of 1.76 that of Jupiter.
[edit] Orbit and mass
Gamma Cephei moves between 1.7 and 2.5 AUs in orbital distance around Gamma Cephei A, with an average separation of around 1.8 AUs, which would be between the orbital distance of Earth and Mars in the solar system. It's orbit is eccentric by 0.19 and takes 2.47 years to complete.
[edit] See also
[edit] References
- Hatzes et al. (2003). "A Planetary Companion to Gamma Cephei A". The Astrophysical Journal 599: 1383-1394.
[edit] External links
- McDonald Observatory: Planet Search finds first planet orbiting close-in binary star
- A Planetary Companion to the Binary Star Gamma Cephei
- SolStation: Errai 2
- Extrasolar Planets Encyclopaedia: Gamma Cephei b
- Extrasolar Visions: Gamma Cephei Ab
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