HD 4747
| Observation data Epoch J2000.0 Equinox J2000.0 | ||
|---|---|---|
| Constellation | Cetus | |
| Right ascension | 00h 49m 26.76537s[1] | |
| Declination | −23° 12′ 44.9359″[1] | |
| Apparent magnitude (V) | 7.155[2] | |
| Characteristics | ||
| Spectral type | G8V + L9[3] | |
| B−V color index | 0.769[3] | |
| Absolute magnitude (MV) | 5.94 | |
Semi-amplitude (K1) (primary) 0.7553+0.0124 | −0.0116[6] km/s | |
| Details | ||
| HD 4747A | ||
Gyr | ||
| HD 4747B | ||
| Mass | 67.2 ± 1.8[5] MJup | |
| Database references | ||
| SIMBAD | data | |
HD 4747 is a star that lies approximately 61
Binarity
The binarity of HD 4747 was announced in 2002, based on observations with the HIRES spectrograph at the W. M. Keck Observatory.[8] The radial velocity variation caused by the companion was found to have a semi-amplitude of approximately 0.65 km/s, which evaded detection by earlier spectrographs due to their precision being poorer than about 1 km/s, but was easily detectable by the 3 m/s precision of HIRES. With a period of 6832 ± 653 days (the large error due to the orbit being unclosed over 1731 day span of observations) and an eccentricity of 0.64 ± 0.06, assuming a primary mass of 0.83 M☉ led to a minimum secondary mass of 42.3 MJ - well within the brown dwarf regime. HD 4747 B became one of the few brown dwarf candidates orbiting within a few AU of any type of star.
An updated orbital solution was provided in 2010, based on observations with the
In 2013 an attempt to directly image the secondary using
HD 4747B
Photometry indicates that HD 4747B is most likely a L-type brown dwarf and may possibly be close to the transition between L and T-types. A preliminary dynamical mass was found to be 67.2±1.8 times the mass of Jupiter.[5]
References
- ^ S2CID 18759600. Vizier catalog entry
- ^ a b "HD 4747". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2022-12-22.
- ^ .
- ^ S2CID 119276951.
- ^ S2CID 251280107.
- ^ S2CID 38430082.
- ^ doi:10.1086/430500.
- ^ S2CID 51814894.
- S2CID 16256304.
