38 Virginis

38 Virginis
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Virgo
Right ascension 12h 53m 11.3s[1]
Declination −03° 33′ 11″[1]
Apparent magnitude (V) 6.11
Characteristics
Spectral type F6V[2]
B−V color index 0.49[2]
Astrometry
Parallax (π)30.55 ± 0.30[2] mas
Distance107 ± 1 ly
(32.7 ± 0.3 pc)
Absolute magnitude (MV)6.11
Details
Mass1.18 ± 0.12[2] M☉
Radius1.45 ± 0.07[2] R☉
Luminosity3.48[note 1] L☉
Temperature6557 ± 96[2] K
Metallicity [Fe/H]0.07[2] dex
Age1.9+0.6
−0.7[2] Gyr
Other designations
38 Vir, HR 4891, HD 111998, HIP 62875, CCDM J12532-0333
Database references
SIMBADdata

38 Virginis is an F-type main sequence star in the constellation of Virgo. To view it, binoculars or a telescope are necessary, as it is too faint to be visible to the naked eye. It is around 107 light years distant from the Earth.[2]

Nomenclature

The name 38 Virginis derives directly the star being catalogued as the 38th star discovered in the constellation Virgo. 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.[3] 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[4] and has a temperature of 5778 K.[5]

The star is metal-rich, with a metallicity ([Fe/H]) of 0.07, 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.[6]

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 — ~1.05 RJ

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. It's orbit very likely puts it and any moons it may have in the habitable zone of its star.

Notes

  1. ↑ From , where is the luminosity, is the radius, is the effective surface temperature and is the Stefan–Boltzmann constant.

References

  1. 1 2 "Notes for 38 Vir b". Extrasolar Planets Encyclopedia. Retrieved 18 September 2016.
  2. 1 2 3 4 5 6 7 8 9 10 11 Borgniet, Simon; Lagrange, Anne-Marie; Meunier, Nadège; Galland, Franck (2016). "Extrasolar planets and brown dwarfs around AF-type stars. IX. The HARPS southern sample". arXiv:1608.08257Freely accessible [astro-ph.EP].
  3. ↑ 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:1012.0707Freely accessible [astro-ph.SR].
  4. ↑ Fraser Cain (16 September 2008). "How Old is the Sun?". Universe Today. Retrieved 19 February 2011.
  5. ↑ Fraser Cain (15 September 2008). "Temperature of the Sun". Universe Today. Retrieved 19 February 2011.
  6. ↑ J. Dommanget; et al. (February 2002), "Catalog of Components of Double & Multiple Stars", Observations et Travaux, Societe Astronomique de France

Coordinates: 12h 53m 11.3s, −03° 33′ 11″

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