Astronomy:38 Virginis
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Virgo[1] |
| Right ascension | 12h 53m 11.15678s[2] |
| Declination | −03° 33′ 11.1513″[2] |
| Apparent magnitude (V) | 6.135±0.037[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | F6V[4] |
| B−V color index | 0.49[4] |
| Astrometry | |
| Radial velocity (Rv) | −7.30±0.32[5] km/s |
| Proper motion (μ) | RA: −262.971[2] mas/yr Dec.: −3.649[2] mas/yr |
| Parallax (π) | 29.9081 ± 0.0377[2] mas |
| Distance | 109.1 ± 0.1 ly (33.44 ± 0.04 pc) |
| Details | |
| Mass | 1.18±0.12[4] M☉ |
| Radius | 1.45±0.07[4] R☉ |
| Luminosity | 3.48[note 1] L☉ |
| Temperature | 6557±96[4] K |
| Metallicity [Fe/H] | +0.07[4] dex |
| Age | 1.9+0.6 −0.7[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
38 Virginis is an F-type main sequence star in the constellation of Virgo. With an apparent magnitude of 6.135,[3] it is very close to the average threshold for naked eye visibility, and can only be viewed from sufficiently dark skies, far from light pollution.[7] It is around 109.1 light years distant from the Earth.[2]
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.[8] In the case of 38 Virginis, only one was discovered, which was designated b.[4]
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[9] and has a temperature of 5778 K.[10]
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.[11]
Planetary system
| 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. It has a mass of around 4.5 times that of the planet Jupiter, an orbital period of 825.9 days (2.261 years) and a relatively low eccentricity out of any long-period giant exoplanet discovered, with an eccentricity of 0.03.[4]
The planet lies within the host star's habitable zone. As of 2024[update], it is the only known planet around a F-type star that is always orbiting inside the habitable zone, as opposed to an orbit that never or just occasionally crosses the HZ.[12]
Notes
- ↑ From , where is the luminosity, is the radius, is the effective surface temperature and is the Stefan–Boltzmann constant.
References
- ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 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.
- ↑ 3.0 3.1 Paunzen, E. (2015-08-01). "A new catalogue of Strömgren-Crawford uvbyβ photometry". Astronomy and Astrophysics 580: A23. doi:10.1051/0004-6361/201526413. ISSN 0004-6361. Bibcode: 2015A&A...580A..23P.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 Borgniet, S. et al. (2017). "Extrasolar planets and brown dwarfs around AF-type stars. IX. The HARPS southern sample". Astronomy and Astrophysics 599: A57. doi:10.1051/0004-6361/201628805. Bibcode: 2017A&A...599A..57B.
- ↑ Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ "38 Virginis". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=38+Virginis.
- ↑ "Limiting Magnitude | COSMOS". https://astronomy.swin.edu.au/cosmos/l/Limiting+Magnitude.
- ↑ 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].
- ↑ Fraser Cain (16 September 2008). "How Old is the Sun?". Universe Today. http://www.universetoday.com/18237/how-old-is-the-sun/.
- ↑ Fraser Cain (15 September 2008). "Temperature of the Sun". Universe Today. http://www.universetoday.com/18092/temperature-of-the-sun/.
- ↑ J. Dommanget (February 2002), Catalog of Components of Double & Multiple Stars, Observations et Travaux, Societe Astronomique de France
- ↑ Patel, Shaan D.; Cuntz, Manfred; Weinberg, Nevin N. (September 2024). "Statistics and Habitability of F-type Star–Planet Systems" (in en). The Astrophysical Journal Supplement Series 274 (1): 20. doi:10.3847/1538-4365/ad65eb. ISSN 0067-0049. Bibcode: 2024ApJS..274...20P.
Coordinates: 
12h 53m 11.3s, −03° 33′ 11″
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