| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 02h 42m 21.3071s[1] |
| Declination | +38° 37′ 07.1392″[1] |
| Apparent magnitude (V) | 8.74[citation needed] |
| Characteristics | |
| Spectral type | G5V[2] |
| B−Vcolor index | 0.715[2] |
| Astrometry | |
| Proper motion (μ) | RA: 78.493±0.760[1]mas/yr Dec.: −100.691±0.717[1]mas/yr |
| Parallax (π) | 14.3851±0.4554 mas[1] |
| Distance | 227 ± 7 ly (70 ± 2 pc) |
| Absolute magnitude (MV) | 5.41[2] |
| Orbit[3] | |
| Companion | HD 16760 b |
| Period (P) | 466.048±0.057 d |
| Semi-major axis (a) | 1.161±0.097 AU |
| Eccentricity (e) | 0.0812±0.0018 |
| Inclination (i) | 3.164+0.810 −0.762[4]° |
| Periastronepoch (T) | 24513802.6±1.9 |
| Argument of periastron (ω) (secondary) | 241.9±1.4° |
| Semi-amplitude (K1) (primary) | 407.16±0.71 km/s |
| Details | |
| HD 16760 A | |
| Mass | 0.78 ± 0.05[2] M☉ |
| Radius | 0.81 ± 0.27[2] R☉ |
| Luminosity (bolometric) | 0.72 ± 0.43[2] L☉ |
| Surface gravity (log g) | 4.47 ± 0.06[2] cgs |
| Temperature | 5629 ± 44[2] K |
| Metallicity [Fe/H] | +0.067 ± 0.05[2] dex |
| Rotational velocity (v sin i) | 0.5 ± 0.5[2] km/s |
| Age | 1.3 ± 0.9[5] Gyr |
| HD 16760 b | |
| Mass | 291.9+120.7 −69.4[4] MJup |
| HIP 12635 | |
| Mass | 0.267±0.014[6] M☉ |
| Other designations | |
| 2MASS J02422130+3837073,BD+37°604,GSC 02845-02243,HIP 12638,SAO 55798,TYC 2845-2243-1 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 16760 is abinary star system approximately 227light-years away in theconstellationPerseus. The primary starHD 16760 (HIP 12638) is aG-type main sequence star similar to theSun. The secondary,HIP 12635 is 1.521 magnitudes fainter and located at a separation of 14.6arcseconds from the primary, corresponding to a physical separation of at least 660AU. Announced in July 2009, HD 16760 has been confirmed to have ared dwarf orbiting it, formerly thought to be abrown dwarf orexoplanet.[2][7][4]
The companion object was discovered independently by theSOPHIE extrasolar planets program[7] and theN2K Consortium.[2] It has a mass exceeding the lower limit required for fusion ofdeuterium in its interior. This criterion is sometimes used to distinguish between brown dwarfs, which lie above the limit, and planets which lie below the limit.[8] However its orbit is nearly circular, indicating that it may have formed in the same way as planets do, from a circumstellar disc.[7] The formation of massive planets up to 20–25Jupiter masses has been predicted in some models of the core accretion process.[9] The identity of this object as a brown dwarf or a massive planet was thus unclear.
However, data analysed from direct imaging of the companion object using ground-based telescopes fitted withadaptive optics has revealed that it is aligned in a much more face-onorbit than previously realised. Consequently, its mass has been revised upwards. It is now no longer believed to be a largegas giant or even a brown dwarf but with a new mass calculated at around one quarterthat of the Sun, or nearly 300 Jupiter masses, it easily qualifies as a stellar object, probably a red dwarf.[10] This was confirmed byGaiaastrometry in 2020.[4]
