Delta Virginis

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Delta Virginis
Diagram showing star positions and boundaries of the Virgo constellation and its surroundings
Cercle rouge 100%.svg

Location of δ Virginis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Virgo
Right ascension 12h 55m 36.20861s[1]
Declination +3° 23′ 50.8932″[1]
Apparent magnitude (V) 3.402[2]
Characteristics
Spectral type M3 III[3]
U−B color index +1.825[2]
B−V color index +1.565[2]
Variable type Semiregular
Astrometry
Radial velocity (Rv) –18.14 ± 0.55[4] km/s
Proper motion (μ) RA: –469.99[1] mas/yr
Dec.: –52.83[1] mas/yr
Parallax (π) 16.44 ± 0.22[1] mas
Distance 198 ± 3 ly
(60.8 ± 0.8 pc)
Absolute magnitude (MV) –2.4 ± 0.3[5]
Details
Mass 1.4 ± 0.3[5] M
Radius 48[4] R
Luminosity 468[4] L
Surface gravity (log g) 1.0[4] cgs
Temperature 3,999[4] K
Metallicity [Fe/H] –0.16[4] dex
Rotational velocity (v sin i) 6.0[4] km/s
Other designations
Auva, Minelauva, 43 Virginis, BD +04°2669, FK5 484, HD 112300, HIP 63090, HR 4910, LTT 13714, SAO 119674.[6]

Delta Virginis (δ Vir, δ Virginis) is a star in the zodiac constellation of Virgo. It has the traditional name Auva. With an apparent visual magnitude of 3.4,[2] this star is bright enough to be seen with the naked eye. Based upon parallax measurements, it is located at a distance of about 198 light-years (61 parsecs) from Earth.[1]

Properties[edit]

The spectrum of this star matches a stellar classification of M3 III,[3] which places it among the category of evolved stars called red giants. Indeed, the outer atmosphere of this star has expanded to around 48 times the radius of the Sun.[4] Even though it has just 1.4 times the mass of the Sun,[5] this wide envelope gives it a luminosity of roughly 468 times the Sun's.[4] This energy is being radiated from a relatively cool outer atmosphere that has an effective temperature of nearly 4,000 K.[4] It is this cool temperature that gives it the orange-red glow of an M-type star.[7]

The outer envelope of this star is undergoing a type of pulsation that occurs in a class of variable stars known as semiregular variables[8] and its brightness varies from magnitude +3.32 to +3.40. Based upon frequency analysis of the observed light curve, the star's variability exhibits multiple periods of pulsation. The detected periods are 13.0, 17.2, 25.6, 110.1 and 125.8 days.[8] This is a high-velocity star with a peculiar velocity of more than 30 km s–1 relative to the mean motion of other stars in the vicinity.[9]

Delta Virginis is a possible binary star, as an 11th magnitude star is located at an angular separation of 80 arcseconds. This K-type dwarf may have an orbital period of over 200,000 years, but this has not been confirmed.[10]

Etymology[edit]

The medieval names Auva, Al Awwa, and Minelauva are from the Arabic عوى cawwa’, meaning "barking (dog)". This star, along with β Vir(Zavijava), γ Vir (Porrima), η Vir (Zaniah) and ε Vir (Vindemiatrix), were Al ʽAwwāʼ, the Barker.[11]

In Chinese, 太微左垣 (Tài Wēi Zuǒ Yuán), meaning Left Wall of Supreme Palace Enclosure, refers to an asterism consisting of δ Virginis, η Virginis, γ Virginis, ε Virginis and α Comae Berenices.[12] Consequently, δ Virginis itself is known as 太微左垣三 (Tài Wēi Zuǒ Yuán sān, English: the Third Star of Left Wall of Supreme Palace Enclosure.),[13] representing 東次相 (Dōngcìxiāng), meaning The Second Eastern Minister.[14] 東次相 (Dōngcìxiāng), westernized into Tsze Seang by R.H. Allen and the meaning is "the Second Minister of State" [15]

References[edit]

  1. ^ a b c d e f 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. ^ a b c d Celis S., L. (October 1975), "Photoelectric photometry of late-type variable stars", Astronomy and Astrophysics Supplement Series 22: 9–17, Bibcode:1975A&AS...22....9C 
  3. ^ a b Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics 352: 495–507, Bibcode:1999A&A...352..495M 
  4. ^ a b c d e f g h i j Massarotti, Alessandro et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209 
  5. ^ a b c Tsuji, T. (October 2008), "Cool luminous stars: the hybrid nature of their infrared spectra", Astronomy and Astrophysics 489 (3): 1271–1289, arXiv:0807.4387, Bibcode:2008A&A...489.1271T, doi:10.1051/0004-6361:200809869 
  6. ^ "del Vir -- Variable Star", SIMBAD (Centre de Données astronomiques de Strasbourg), retrieved 2012-02-07 
  7. ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16 
  8. ^ a b Tabur, V. et al. (December 2009), "Long-term photometry and periods for 261 nearby pulsating M giants", Monthly Notices of the Royal Astronomical Society 400 (4): 1945–1961, arXiv:0908.3228, Bibcode:2009MNRAS.400.1945T, doi:10.1111/j.1365-2966.2009.15588.x 
  9. ^ Famaey, B. et al., "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics 430: 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272 
  10. ^ Kaler, James B., "Delta Virginis", Stars (University of Illinois), retrieved 2012-02-07 
  11. ^ 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 
  12. ^ (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.
  13. ^ (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.
  14. ^ (Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name, Hong Kong Space Museum. Accessed on line November 23, 2010.
  15. ^ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Virgo

External links[edit]