Astronomy:Nu Herculis

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Short description: Variable star in the constellation Hercules
Nu Herculis
Observation data
Equinox J2000.0]] (ICRS)
Constellation Hercules
Right ascension  17h 58m 30.14909s[1]
Declination +30° 11′ 21.3870″[1]
Apparent magnitude (V) 4.38 - 4.48[2]
Characteristics
Spectral type F2II[3] (kA9hF2mF2(IV)[4] + B9.5[5])
U−B color index +0.13[6]
B−V color index +0.35[6]
Variable type SRd?[2]
Astrometry
Radial velocity (Rv)-22.30 ± 0.6[7] km/s
Proper motion (μ) RA: -0.81[1] mas/yr
Dec.: 2.18[1] mas/yr
Parallax (π)3.79 ± 0.39[1] mas
Distanceapprox. 860 ly
(approx. 260 pc)
Absolute magnitude (MV)−2.67[8]
Details
Mass5.31[9] M☉
Luminosity799[10] L☉
Surface gravity (log g)2.29[9] cgs
Temperature6410[9] K
Metallicity [Fe/H]−0.33[11] dex
Rotational velocity (v sin i)28.0[10] km/s
Age200[10] Myr
Other designations
ν Her, BD+30° 3093, HD 164136, HIP 87998, HR 6707, SAO 66524[12]
Database references
SIMBADdata

Nu Herculis, Latinized from ν Herculis, is a binary and variable star in the constellation of Hercules. With an apparent magnitude of about 4.4, it is faintly visible to the naked eye. Parallax measurements made by the Hipparcos spacecraft put it at a distance of about 860 light years (260 parsecs).

This is a binary system with the two components separated by 0.446″. The secondary is nearly three magnitudes fainter than the primary at magnitude 7.5,[13] and is hotter than the primary with a spectral type of B9.5.[5]

Nu Herculis's spectral type of F2 II means that it is an F-type bright giant, with a luminosity 799 times that of the Sun. Its effective temperature is 6,410 K, hotter than the Sun.[9] Its mass is about 5.3 solar masses.[9] It is a possible semiregular variable star with a range of about a tenth of a magnitude. A period of 29 days has been derived.[2]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...474..653VFUL. 
  2. ↑ 2.0 2.1 2.2 Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1. Bibcode: 2009yCat....102025S. 
  3. ↑ Morgan, W. W.; Roman, Nancy G. (1950). "Revised Standards for Supergiants on the System of the Yerkes Spectral Atlas". Astrophysical Journal 112: 362–364. doi:10.1086/145351. Bibcode: 1950ApJ...112..362M. 
  4. ↑ Gray, R. O.; Garrison, R. F. (1989). "The Early F-Type Stars: Refined Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation". The Astrophysical Journal Supplement Series 69: 301. doi:10.1086/191315. Bibcode: 1989ApJS...69..301G. 
  5. ↑ 5.0 5.1 Parsons, Sidney B.; Ake, Thomas B. (1998). "Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample". The Astrophysical Journal Supplement Series 119 (1): 83. doi:10.1086/313152. Bibcode: 1998ApJS..119...83P. 
  6. ↑ 6.0 6.1 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data: 0. Bibcode: 1986EgUBV........0M. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1. Retrieved 2017-03-09. 
  7. ↑ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G. 
  8. ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  9. ↑ 9.0 9.1 9.2 9.3 9.4 Lyubimkov, Leonid S.; Lambert, David L.; Kaminsky, Bogdan M.; Pavlenko, Yakov V.; Poklad, Dmitry B.; Rachkovskaya, Tamara M. (2012). "Lithium abundance in atmospheres of F- and G-type supergiants and bright giants". Monthly Notices of the Royal Astronomical Society 427 (1): 11–26. doi:10.1111/j.1365-2966.2012.21617.x. Bibcode: 2012MNRAS.427...11L. 
  10. ↑ 10.0 10.1 10.2 Mallik, Sushma V.; Parthasarathy, M.; Pati, A. K. (2003). "Lithium and rotation in F and G dwarfs and subgiants". Astronomy and Astrophysics 409: 251–261. doi:10.1051/0004-6361:20031084. Bibcode: 2003A&A...409..251M. 
  11. ↑ Luck, R. Earle (2014). "Parameters and Abundances in Luminous Stars". The Astronomical Journal 147 (6): 137. doi:10.1088/0004-6256/147/6/137. Bibcode: 2014AJ....147..137L. 
  12. ↑ "nu. Her". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=nu.+Her. 
  13. ↑ EAS (1997). "The HIPPARCOS and TYCHO catalogues". Astrometric and Photometric Star Catalogues Derived from the ESA Hipparcos Space Astrometry Mission. ESA SP Series (Noordwijk, Netherlands: ESA Publications Division) 1200. ISBN 9290923997. Bibcode: 1997ESASP1200.....E. 



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