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).
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| 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 mas[1] |
| Distance | approx. 860 ly (approx. 260 pc) |
| Absolute magnitude (MV) | −2.67[8] |
| Details | |
| Mass | 5.31[9] M☉ |
| Luminosity | 799[10] L☉ |
| Surface gravity (log g) | 2.29[9] cgs |
| Temperature | 6410[9] K |
| Metallicity [Fe/H] | −0.33[11] dex |
| Rotational velocity (v sin i) | 28.0[10] km/s |
| Age | 200[10] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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
edit- ^ a b c d e van Leeuwen, F.; et al. (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. S2CID 18759600.
- ^ a b c Samus, N. N.; Durlevich, O. V.; 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.
- ^ Morgan, W. W.; Roman, Nancy G. (1950). "Revised Standards for Supergiants on the System of the Yerkes Spectral Atlas". Astrophysical Journal. 112: 362–364. Bibcode:1950ApJ...112..362M. doi:10.1086/145351.
- ^ 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. Bibcode:1989ApJS...69..301G. doi:10.1086/191315.
- ^ a b 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. Bibcode:1998ApJS..119...83P. doi:10.1086/313152.
- ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data: 0. Bibcode:1986EgUBV........0M. Archived from the original on 2019-12-08. Retrieved 2017-03-09.
- ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
- ^ 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, S2CID 119257644.
- ^ a b c d e 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. arXiv:1212.6057. Bibcode:2012MNRAS.427...11L. doi:10.1111/j.1365-2966.2012.21617.x. S2CID 119191810.
- ^ a b c 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. Bibcode:2003A&A...409..251M. doi:10.1051/0004-6361:20031084.
- ^ Luck, R. Earle (2014). "Parameters and Abundances in Luminous Stars". The Astronomical Journal. 147 (6): 137. Bibcode:2014AJ....147..137L. doi:10.1088/0004-6256/147/6/137.
- ^ "nu. Her". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 5 March 2017.
- ^ EAS (1997). "The HIPPARCOS and TYCHO catalogues". Astrometric and Photometric Star Catalogues Derived from the ESA Hipparcos Space Astrometry Mission. ESA SP Series. 1200. Noordwijk, Netherlands: ESA Publications Division. Bibcode:1997ESASP1200.....E. ISBN 9290923997.