27 Hydrae
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 09h 20m 29.0181s |
| Declination | −09° 33′ 20.501″ |
| Apparent magnitude (V) | 4.82 |
| Characteristics | |
| Spectral type | G8III-IV/?M5V |
| B−V color index | 0.92 |
| Astrometry | |
| Distance | 243.4 ly (74.68 pc) |
| Details | |
| Mass | 2.32/≥0.25 M☉ |
| Radius | ≈8/0.3? R☉ |
| Luminosity | 40.3/0.0074? L☉ |
| Temperature | 5150/>3100? K |
| Orbit | |
| Period (P) | ≈1.6 million yr |
| Semi-major axis (a) | 15,800 AUs" |
| Other designations | |
27 Hydrae is an evolved yellow giant star in the constellation of Hydra. The star is suspected to host a low-mass companion.
Substellar companion
The Okayama Planet Search team published a paper in late 2008 reporting investigations into radial velocity variations observed for a set of evolved stars, showing hints of a substellar companion orbiting the wide binary system 27 Hydrae.[1] The orbital period is estimated at 9.3 years, but no planet has been confirmed yet.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | ≥10 MJ | ≈5.9 | 3400 | ? | — | — |
References
- ↑ Toyota; et al. (2008). "Radial Velocity Search for Extrasolar Planets in Visual Binary Systems". Publications of the Astronomical Society of Japan 61 (1): 19–28. Bibcode:2009PASJ...61...19T. doi:10.1093/pasj/61.1.19.
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