HD 27631 is a star with an orbiting exoplanet in the southern constellation of Horologium. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 8.24.[2] The distance to this system is 164 light years based on parallax measurements. It is drifting further away with a radial velocity of 21 km/s.[1]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Horologium |
| Right ascension | 04h 19m 45.46920s[1] |
| Declination | –41° 57′ 36.9527″[1] |
| Apparent magnitude (V) | 8.243±0.012[2] |
| Characteristics | |
| Spectral type | G3IV[2] |
| B−V color index | 0.721±0.009[2] |
| Astrometry | |
| Radial velocity (Rv) | 21.04±0.13[1] km/s |
| Proper motion (μ) | RA: –41.139 mas/yr[1] Dec.: –91.908 mas/yr[1] |
| Parallax (π) | 19.9263 ± 0.0160 mas[1] |
| Distance | 163.7 ± 0.1 ly (50.18 ± 0.04 pc) |
| Absolute magnitude (MV) | 4.97[3] |
| Details[2] | |
| Mass | 0.944±0.032 M☉ |
| Radius | 0.923±0.033 R☉ |
| Luminosity | 0.97[3] L☉ |
| Surface gravity (log g) | 4.455±0.038 cgs |
| Temperature | 5,737±36 K |
| Metallicity [Fe/H] | −0.12±0.05 dex |
| Rotation | ~31 d |
| Age | 4.010±2.892 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This is a G-type star with a stellar classification of G3IV,[2] suggesting it is a subgiant star that is evolving off the main sequence after exhausting the supply of hydrogen at its core. It is smaller than the Sun, with 94% of its mass and 92% of the radius.[2] The star is radiating 97%[3] of the luminosity of the Sun from its photosphere at an effective temperature of 5,737 K.[2] The estimated age is roughly 4.4 billion years[5] and it is spinning slowly with a rotation period of around 31 days.[2]
A survey in 2015 has ruled out the existence of any stellar companions at projected distances above 40 astronomical units.[6]
Planetary system
editFrom 1998 to 2012, the star was under observation from the CORALIE echelle spectrograph at La Silla Observatory. In 2012, a long-period, wide-orbiting exoplanet was deduced by radial velocity. This was published in November.[5] In 2023, the inclination and true mass of HD 27631 b were determined via astrometry.[7] This is a super-jovian planet with around 1.6 times the mass of Jupiter. It is orbiting the host star at a separation of 3.22 AU with an eccentricity (ovalness) of 0.16 and an orbital period of six years.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 1.56+0.2 −0.15 MJ |
3.22+0.065 −0.064 |
5.95+0.13 −0.12 |
0.163±0.057 | 74+11 −15 or 106+15 −11° |
— |
References
edit- ^ a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e f g h i Barbato, D.; et al. (August 2018). "Exploring the realm of scaled solar system analogues with HARPS". Astronomy & Astrophysics. 615: 21. arXiv:1804.08329. Bibcode:2018A&A...615A.175B. doi:10.1051/0004-6361/201832791. S2CID 119099721. A175.
- ^ a b c Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
- ^ "HD 27631". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-12-12.
- ^ a b Marmier, M.; et al. (2013). "The CORALIE survey for southern extrasolar planets XVII. New and updated long period and massive planets". Astronomy and Astrophysics. 551. A90. arXiv:1211.6444. Bibcode:2013A&A...551A..90M. doi:10.1051/0004-6361/201219639. S2CID 59467665.
- ^ Mugrauer, M.; Ginski, C. (12 May 2015). "High-contrast imaging search for stellar and substellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 450 (3): 3127–3136. Bibcode:2015MNRAS.450.3127M. doi:10.1093/mnras/stv771. hdl:1887/49340. Retrieved 19 June 2020.
- ^ a b Xiao, Guang-Yao; Liu, Yu-Juan; et al. (March 2023). "The Masses of a Sample of Radial-Velocity Exoplanets with Astrometric Measurements". Research in Astronomy and Astrophysics. arXiv:2303.12409.