Astronomy:HD 27631

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Short description: Star in the constellation Horologium

Coordinates: Sky map 04h 19m 45.46920s, −41° 57′ 36.9527″

HD 27631
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
Distance163.7 ± 0.1 ly
(50.18 ± 0.04 pc)
Absolute magnitude (MV)4.97[3]
Details[2]
Mass0.944±0.032 M
Radius0.923±0.033 R
Luminosity0.97[3] L
Surface gravity (log g)4.455±0.038 cgs
Temperature5,737±36 K
Metallicity [Fe/H]−0.12±0.05 dex
Rotation~31 d
Age4.010±2.892 Gyr
Other designations
CD−42°1464, HD 27631, HIP 20199, SAO 216753[4]
Database references
SIMBADdata
Exoplanet Archivedata
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.

The HD 27631 planetary system[7]
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. Jump up to: 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. Jump up to: 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. Bibcode2018A&A...615A.175B. 
  3. Jump up to: 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. Bibcode2012AstL...38..331A. 
  4. "HD 27631". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+27631. 
  5. Jump up to: 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. Bibcode2013A&A...551A..90M. 
  6. 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. Bibcode2015MNRAS.450.3127M. https://academic.oup.com/mnras/article/450/3/3127/1063872. Retrieved 19 June 2020. 
  7. Jump up to: 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. 

External links