Upsilon1 Hydrae
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 09h 51m 28.6937s |
| Declination | −14° 50′ 47.771″ |
| Apparent magnitude (V) | 4.12 |
| Characteristics | |
| Spectral type | G6/8III[1] |
| Astrometry | |
| Distance | 273.48 ly (83.89 pc) |
| Details | |
| Mass | 3.34 [1] M☉ |
| Radius | 17.1 R☉ |
| Luminosity | 174[1] L☉ |
| Temperature | 5045[1] K |
| Age | 270[1] million years |
| Other designations | |
Upsilon 1 Hya, 39 Hya, HD 85444, BD-14 2963, HIP 48356, HR 3903, SAO 155542. | |
Upsilon1 Hydrae is a yellow giant star in the constellation of Hydra. The star is one of Okayama Planet Search's main target for planet search and has turned out to host a substellar companion.
Substellar companion
The Okayama Planet Search team published a paper in 2005 reporting investigations on radial velocity variations observed for a set of orange giant stars and announcing the detection of a brown dwarf companion in an eccentric orbit around Upsilon1 Hydrae.[2] The orbital period is roughly 4.1 years.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥49 MJ | 3.9 | 1500 | 0.57 | — | — |
References
- 1 2 3 4 5 Takeda; et al. (2008). "Stellar Parameters and Elemental Abundances of Late-G Giants". Publications of the Astronomical Society of Japan. 60 (4): 781–802. arXiv:0805.2434
. Bibcode:2008PASJ...60..781T. doi:10.1093/pasj/60.4.781. - ↑ Sato; et al. (2005). "Radial-Velocity Variability of G-Type Giants: First Three Years of the Okayama Planet Search Program". Publications of the Astronomical Society of Japan. 57 (1): 97–107. Bibcode:2005PASJ...57...97S. doi:10.1093/pasj/57.1.97.
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