Epsilon Virginis

Epsilon Virginis
Diagram showing star positions and boundaries of the Virgo constellation and its surroundings


Location of ε Virginis (circled)

Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Virgo
Right ascension 13h 02m 10.59785s[1]
Declination +10° 57′ 32.9415″[1]
Apparent magnitude (V) +2.826[2]
Characteristics
Spectral type G8 III[3]
U−B color index +0.718[2]
B−V color index +0.940[2]
Astrometry
Radial velocity (Rv)-14.6[4] km/s
Proper motion (μ) RA: -273.80[1] mas/yr
Dec.: +19.96[1] mas/yr
Parallax (π)29.76 ± 0.14[1] mas
Distance109.6 ± 0.5 ly
(33.6 ± 0.2 pc)
Absolute magnitude (MV)0.37 ± 0.06[5]
Details
Mass2.64 ± 0.11[5] M☉
Radius10.6 ± 0.3[6] R☉
Luminosity77[7] L☉
Surface gravity (log g)2.71 ± 0.04[5] cgs
Temperature5,086[5] K
Metallicity [Fe/H]+0.09[5] dex
Rotation173 days[8]
Rotational velocity (v sin i)2.3[9] km/s
Age560 ± 90[5] Myr
Other designations
Vindemiatrix, Vindemiator, Almuredin, Provindemiator, Protrigetrix, Protrygetor, Alaraph, 47 Virginis, BD+11 2529, FK5 488, HD 113226, HIP 63608, HR 4932, SAO 100384.[10]

Epsilon Virginis (ε Vir, ε Virginis) is the Bayer designation for a star in the zodiac constellation of Virgo. It has the traditional name Vindemiatrix, which comes from Greek through Latin and means Grape Gatherer. The apparent visual magnitude of this star is +2.8,[2] making it the third brightest member of Virgo. Based upon parallax measurements made during the Hipparcos mission, Vindemiatrix lies at a distance of about 109.6 light-years (33.6 parsecs) from Earth, give or take a half light year.[1]

Vindemiatrix is a giant star with a stellar classification of G8 III.[3] With 2.6[5] times the mass of the Sun, it has reached a stage in its evolution where the hydrogen fuel in its core is exhausted. As a result, it has expanded to over ten[6] times the Sun's girth and is now radiating around 77[7] times as much luminosity as the Sun. This energy is being emitted from its outer atmosphere at an effective temperature of 5,086 K,[5] which gives it the yellow-hued glow of a G-type star. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[11]

This star is following an orbit through the Milky Way with an eccentricity of 0.11. This will carry it as close as 7.25 kpc (23.6 kly) to the Galactic Center, and take it as far as 8.95 kpc (29.2 kly). It is a likely member of the thin disk population and the orbit departs by no more than 60 pc (200 ly) from the galactic plane.[12]

Etymology

The traditional names Vindemiatrix and Vindemiator are from Latin vindēmiātrix, vindēmitor "the grape-harvestress". Additional medieval names are Almuredin, Alaraph, Provindemiator, Protrigetrix, and Protrygetor. This star, along with β Vir(Zavijava), γ Vir (Porrima), η Vir (Zaniah) and δ Vir, (Auva), were Al ʽAwwāʼ, the Barker.[13]

In Chinese, 太微左垣 (Tài Wēi Zuǒ Yuán), meaning Left Wall of Supreme Palace Enclosure, refers to an asterism consisting of ε Virginis, η Virginis, γ Virginis, δ Virginis and α Comae Berenices.[14] Consequently, ε Virginis itself is known as 太微左垣四 (Tài Wēi Zuǒ Yuán sì, English: the Fourth Star of Left Wall of Supreme Palace Enclosure.),[15] representing 東次將 (Dōngcìjiāng), meaning The Second Eastern General.[16] 東次將 (Dōngcìjiāng), westernized into Tsze Tseang by R.H. Allen and the meaning is "the Second General"[17]

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (November 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. 1 2 3 4 Gutierrez-Moreno, Adelina; et al. (1966), A System of photometric standards 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode:1966PDAUC...1....1G
  3. 1 2 Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics 11: 29, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333
  4. ↑ Wielen, R.; et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions 35, Veröffentlichungen des Astronomisches Rechen-Institut Heidelberg, Bibcode:1999VeARI..35....1W
  5. 1 2 3 4 5 6 7 8 da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105
  6. 1 2 Nordgren, Tyler E.; et al. (December 1999), "Stellar Angular Diameters of Late-Type Giants and Supergiants Measured with the Navy Prototype Optical Interferometer", The Astronomical Journal 118 (6): 3032–3038, Bibcode:1999AJ....118.3032N, doi:10.1086/301114
  7. 1 2 Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics 352: 495–507, Bibcode:1999A&A...352..495M
  8. ↑ Setiawan, J.; et al. (July 2004), "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch", Astronomy and Astrophysics 421: 241–254, Bibcode:2004A&A...421..241S, doi:10.1051/0004-6361:20041042-1
  9. ↑ Pizzolato, N.; Maggio, A.; Sciortino, S. (September 2000), "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases", Astronomy and Astrophysics 361: 614–628, Bibcode:2000A&A...361..614P
  10. ↑ Database entry for Epsilon Viginis, SIMBAD. Accessed online May 10, 2010.
  11. ↑ Garrison, R. F. (December 1993), "Anchor Points for the MK System of Spectral Classification", Bulletin of the American Astronomical Society 25: 1319, Bibcode:1993AAS...183.1710G, retrieved 2012-02-04
  12. ↑ Soubiran, C.; et al. (2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics 480 (1): 91–101, arXiv:0712.1370, Bibcode:2008A&A...480...91S, doi:10.1051/0004-6361:20078788
  13. ↑ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, p. 469, ISBN 0-486-21079-0, retrieved 2010-12-12
  14. ↑ (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  15. ↑ (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.
  16. ↑ (Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name, Hong Kong Space Museum. Accessed on line November 23, 2010.
  17. ↑ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Virgo

External links

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