HD 219828
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| Observation data Epoch 2000 |
|
|---|---|
| Constellation (pronunciation) |
Pegasus |
| Right ascension | 23h 18m 47s |
| Declination | +18° 38′ 45″ |
| Apparent magnitude (V) | +8.04 |
| Distance | 264.5 ly (81.1 pc) |
| Spectral type | G0IV |
| Other designations | |
HD 219828 is an eighth magnitude star in the constellation Pegasus. It is a yellow subgiant, meaning that hydrogen fusion has ceased in its core.
In 2007, a Neptune-mass planet is found orbiting the star by Melo.
Contents |
[edit] HD 219828 b
| Extrasolar planet | List of extrasolar planets | |
|---|---|---|
| Orbital elements | ||
| Semimajor axis | (a) | 0.052 AU |
| Eccentricity | (e) | 0 |
| Orbital period | (P) | 3.8335 ± 0.0013 d |
| Angular distance | (θ) | 0.641 mas |
| Longitude of periastron |
(ω) | 0° |
| Time of periastron | (T0) | 2,453,898.6289 ± 0.072 JD |
| Semi-amplitude | (K) | 7 ± 50 m/s |
| Physical characteristics | ||
| Mass | (m) | >0.066 MJ (>21 M⊕) |
| Discovery information | ||
| Discovery date | Feb 18, 2007 | |
| Discoverer(s) | Melo et al. | |
| Detection method | radial velocity | |
| Discovery status | Published | |
HD 219828 b is a Neptune-mass planet at least 21 times more massive than Earth. The planet's composition is unknown, but it may be similar to the ice giants Uranus and Neptune, or alternatively it may be a mainly rocky Super-Earth.
[edit] References
- Melo et al. (05-2007). "A new Neptune-mass planet orbiting HD 219828". Astronomy and Astrophysics 467: 721–727. doi:.
[edit] See also
[edit] External links
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