HD 29587
Star in the constellation Perseus
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HD 29587 is a Sun-like[7] star with a candidate brown dwarf companion[8] in the northern constellation of Perseus. It has an apparent visual magnitude of 7.29,[1] which means it is too faint to be viewed with the naked eye. Based upon an annual parallax shift of 36.6 mas,[2] it is located 89.8 light years away. The star is moving away from the Earth with a heliocentric radial velocity of +113 km/s,[2] having come to within 55.8 ly some 148,000 years ago.[1] It is a hyper-velocity halo[7] star moving at a rate of 170 km/s relative to the local standard of rest.[9]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Perseus[1] |
| Right ascension | 04h 41m 36.31556s[2] |
| Declination | +42° 07′ 06.4241″[2] |
| Apparent magnitude (V) | 7.29[1] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | G2 V[3] |
| B−V color index | 0.633[3] |
| Astrometry | |
| Radial velocity (Rv) | +112.75±0.16[2] km/s |
| Proper motion (μ) | RA: +534.631[2] mas/yr Dec.: −414.946[2] mas/yr |
| Parallax (π) | 36.6470±0.0410 mas[2] |
| Distance | 89.00 ± 0.10 ly (27.29 ± 0.03 pc) |
| Absolute magnitude (MV) | 5.08[3] |
| Orbit[4] | |
| Period (P) | 1,474.9±10.2 d |
| Eccentricity (e) | 0.713±0.006[5] |
| Periastron epoch (T) | JD 2,447,763.5±45.8 |
| Argument of periastron (ω) (secondary) | 80.2±13.3° |
| Semi-amplitude (K1) (primary) | 1.02±0.16 km/s |
| Details[3] | |
| Mass | 1.033±0.010[5] M☉ |
| Radius | 0.91 [a] R☉ |
| Luminosity | 0.798+0.040 −0.038 L☉ |
| Surface gravity (log g) | 4.54±0.22 cgs |
| Temperature | 5,709±35 K |
| Metallicity [Fe/H] | −0.51±0.05 dex |
| Age | 14.7+3.8 −2.7 Gyr |
| Other designations | |
| BD+41°931, FK5 4419, HD 29587, HIP 21832, SAO 39690, TYC 2901-00064-1, 2MASS J04413631+4207065[6] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This ancient star has a stellar classification of G2 V,[3] matching a G-type main-sequence star. It has 78% of the mass of the Sun and is radiating 80% of the Sun's luminosity from its photosphere at an effective temperature of 5,709 K.[3]
Planetary system
Formerly an IAU radial velocity standard, this star was found to have a variable radial velocity due to a suspected orbiting companion.[8] The a sin i value for the unseen object is 0.0957 ± 0.0108 AU (14.31 ± 1.62 Gm),[4] where a is the semimajor axis and i is the orbital inclination – providing a lower bound for the semimajor axis. The secondary object most likely has a mass in the range 41.0–97.8 MJ, making it a probable brown dwarf.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b | ≥ 55.2±9.2[5] MJ | 2.57 [b] | 1,474.9±10.2 | 0.356±0.095 | — | — |
