74 Virginis

74 Virginis is a single[7] star in the zodiac constellation of Virgo.[6] It is visible to the naked eye as a faint red-hued star with an apparent visual magnitude of 4.69.[2] The star is positioned near the ecliptic and thus is subject to lunar occultations.[8] The measured annual parallax of 8.16 mas[1] provides a distance estimate of around 400 light years from the Sun. At that range, the visual magnitude of the star is diminished by an extinction of 0.46±0.02 due to interstellar dust.[2] It is moving further from the Earth with a heliocentric radial velocity of +19 km/s.[4]

This article is about l Virginis. It is not to be confused with ι (iota) Virginis or i Virginis.
74 Virginis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Virgo
Right ascension  13h 31m 57.88506s[1]
Declination −06° 15′ 20.9419″[1]
Apparent magnitude (V) 4.69±0.01[2]
Characteristics
Spectral type M2.5 III[3]
B−V color index 1.606±0.035
Astrometry
Radial velocity (Rv)+18.71±0.15[4] km/s
Proper motion (μ) RA: −103.94[1] mas/yr
Dec.: −43.87[1] mas/yr
Parallax (π)8.16 ± 0.19[1] mas
Distance400 ± 9 ly
(123 ± 3 pc)
Absolute magnitude (MV)−0.76[5]
Details[2]
Mass1.40±0.12 M☉
Radius78.38+1.98
−1.90 R☉
Luminosity831.5±56.8 L☉
Temperature3,500±46 K
Metallicity [Fe/H]0.00 dex
Age2.90±0.68 Gyr
Other designations
l Vir, 74 Vir, NSV 6297, BD−05°3714, FK5 3079, HD 117675, HIP 66006, HR 5095, SAO 139390[6]
Database references
SIMBADdata

This is an aging red giant star with a stellar classification of M2.5 III,[3] which indicates it has exhausted the hydrogen at its core and evolved away from the main sequence. It is a suspected variable star that may vary in brightness with an amplitude of 0.07 in magnitude.[9] The star is roughly 2.9 billion years old with 1.4 times the mass of the Sun and has expanded to around 78 times the Sun's radius. 74 Virginis is radiating 832 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,500 K.[2]

References
  1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. Baines, Ellyn K.; et al. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal, 155, 30, arXiv:1712.08109, Bibcode:2018AJ....155...30B, doi:10.3847/1538-3881/aa9d8b.
  3. Keenan, Philip C; McNeil, Raymond C (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373
  4. Famaey, B.; et al. (2009), "Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations", Astronomy and Astrophysics, 498 (2): 627–640, arXiv:0901.0934, Bibcode:2009A&A...498..627F, doi:10.1051/0004-6361/200810698.
  5. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  6. "74 Vir". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-02-13.
  7. Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  8. Antal, M. (1962), "Observations of occultations at the Observatory Skalnaté Pleso in the year 1961", Bulletin of the Astronomical Institute of Czechoslovakia, 13: 164, Bibcode:1962BAICz..13..164A.
  9. Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S.
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