38 Virginis

38 Virginis

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Virgo
Right ascension	12^h 53^m 11.1564^s[1]
Declination	−03° 33′ 11.1482″[1]
Apparent magnitude (V)	6.11
Characteristics
Spectral type	F6V[2]
B−V color index	0.49[2]
Astrometry
Proper motion (μ)	RA: −262.638±0.113[1] mas/yr Dec.: −3.853±0.100[1] mas/yr
Parallax (π)	30.0702 ± 0.0541 mas[1]
Distance	108.5 ± 0.2 ly (33.26 ± 0.06 pc)
Details
Mass	1.18 ± 0.12[2] M☉
Radius	1.45 ± 0.07[2] R☉
Luminosity	3.48[note 1] L☉
Temperature	6557 ± 96[2] K
Metallicity [Fe/H]	0.07[2] dex
Age	1.9+0.6 −0.7[2] Gyr
Other designations
BD−02 3593, HD 111998, HIP 62875, HR 4891, WDS J12532-0333AB[3]
Database references
SIMBAD	data

38 Virginis is an F-type main sequence star in the constellation of Virgo. It is around 108 light years distant from the Earth.[2][1]

Nomenclature

The name 38 Virginis derives from the star being the 38th star in order of right ascension catalogued in the constellation Virgo by Flamsteed in his star catalogue. The designation b of 38 Virginis b derives from the order of discovery and is given to the first planet orbiting a given star, followed by the other lowercase letters of the alphabet.[4] In the case of 38 Virginis, only one was discovered, which was designated b.[2]

Stellar characteristics

38 Virginis is an F-type main sequence star that is approximately 118% the mass of and 145% the radius of the Sun. It has a temperature of 6557 K and is about 1.9 billion years old. In comparison, the Sun is about 4.6 billion years old[5] and has a temperature of 5778 K.[6]

The star is metal-rich, with a metallicity ([Fe/H]) of 0.07 dex, or 117% the solar amount. Its luminosity (L_☉) is 3.48 times that of the Sun.

A companion star is cataloged in the CCDM at a separation of half an arcsecond.[7]

Planetary system

The 38 Virginis planetary system[2]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	4.51 ± 0.5 MJ	1.82 ± 0.07	825.9 ± 6.2	0.03 ± 0.04	—	—

The star is known to host one exoplanet, 38 Virginis b, discovered in 2016. This planet has a relatively low eccentricity out of any long-period giant exoplanet discovered, with an eccentricity of 0.03. The planet has a mass of around 4.5 times that of the planet Jupiter.[2] Its orbit very likely puts it and any moons it may have in the habitable zone of its star.[8]

Notes

1. From ${\displaystyle {\begin{smallmatrix}L=4\pi R^{2}\sigma T_{\rm {eff}}^{4}\end{smallmatrix}}}$, where ${\displaystyle {\begin{smallmatrix}L\end{smallmatrix}}}$ is the luminosity, ${\displaystyle {\begin{smallmatrix}R\end{smallmatrix}}}$ is the radius, ${\displaystyle {\begin{smallmatrix}T_{\rm {eff}}\end{smallmatrix}}}$ is the effective surface temperature and ${\displaystyle {\begin{smallmatrix}\sigma \end{smallmatrix}}}$ is the Stefan–Boltzmann constant.

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
2. Borgniet, S.; et al. (2017). "Extrasolar planets and brown dwarfs around AF-type stars. IX. The HARPS southern sample". Astronomy and Astrophysics. 599. A57. arXiv:1608.08257. Bibcode:2017A&A...599A..57B. doi:10.1051/0004-6361/201628805. S2CID 118723455.
3. "38 Virginis". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-10-19.
4. Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
5. Fraser Cain (16 September 2008). "How Old is the Sun?". Universe Today. Retrieved 19 February 2011.
6. Fraser Cain (15 September 2008). "Temperature of the Sun". Universe Today. Retrieved 19 February 2011.
7. J. Dommanget; et al. (February 2002), Catalog of Components of Double & Multiple Stars, Observations et Travaux, Societe Astronomique de France
8. Cowing, Keith (2024-09-20). "The Habitability Of F-Type Star Systems". Astrobiology. Retrieved 2024-09-21.