Astronomy:HD 27631
Coordinates: 
04h 19m 45.46920s, −41° 57′ 36.9527″
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[1] mas/yr Dec.: –91.908[1] mas/yr |
| Parallax (π) | 19.9263 ± 0.0160[1] mas |
| 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 |
| Extrasolar Planets Encyclopaedia | data |
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]
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
From 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 astronomical unit|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
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Barbato, D. et al. (August 2018). "Exploring the realm of scaled solar system analogues with HARPS". Astronomy & Astrophysics 615: 21. doi:10.1051/0004-6361/201832791. A175. Bibcode: 2018A&A...615A.175B.
- ↑ 3.0 3.1 3.2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ "HD 27631". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+27631.
- ↑ 5.0 5.1 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. doi:10.1051/0004-6361/201219639. Bibcode: 2013A&A...551A..90M.
- ↑ 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. doi:10.1093/mnras/stv771. Bibcode: 2015MNRAS.450.3127M. https://academic.oup.com/mnras/article/450/3/3127/1063872. Retrieved 19 June 2020.
- ↑ 7.0 7.1 Xiao, Guang-Yao et al. (March 2023). "The Masses of a Sample of Radial-Velocity Exoplanets with Astrometric Measurements". Research in Astronomy and Astrophysics.
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