Astronomy:102 Herculis

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Short description: Star in the constellation Hercules
102 Herculis
Observation data
Equinox J2000.0]] (ICRS)
Constellation Hercules
Right ascension  18h 08m 45.49142s[1]
Declination +20° 48′ 52.4079″[1]
Apparent magnitude (V) 4.37[2]
Characteristics
Spectral type B2 IV[3][4] or B2 V[5][6]
B−V color index −0.164±0.013[2]
Astrometry
Radial velocity (Rv)−14.9±0.6[2] km/s
Proper motion (μ) RA: −1.92[1] mas/yr
Dec.: −5.89[1] mas/yr
Parallax (π)3.56 ± 0.19[1] mas
Distance920 ± 50 ly
(280 ± 10 pc)
Absolute magnitude (MV)−2.87[2]
Details
Mass9.7±0.2[4] M
Luminosity3,631.92[2] L
Surface gravity (log g)3.54[7] cgs
Temperature22,420±1,440[8] K
Rotational velocity (v sin i)41[9] km/s
Age20.0±1.4[4] Myr
Other designations
102 Her, BD+20°3674, FK5 3443, HD 166182, HIP 88886, HR 6787, SAO 85769, WDS J18088+2049[10]
Database references
SIMBADdata

102 Herculis is a single[11] star in the northern constellation of Hercules. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.37.[2] Based upon parallax measurements, it is located around 920 light years away from the Sun.[1] The star is moving closer to the Earth with a heliocentric radial velocity of −15 km/s.[2]

The stellar classification of this object matches a massive, early B-type star with a luminosity class of IV[3] or V,[5] corresponding to a subgiant or main sequence star, respectively. It is 20[4] million years old with nearly ten[4] times the mass of the Sun and is spinning with a projected rotational velocity of 41 km/s.[9] The strength of the stellar magnetic field has been measured at (209.5±135.4)×10−4 T.[6] The star is radiating 3,632[2] times the Sun's luminosity from its photosphere at an effective temperature of 22,420 K.[8]

Etymology

In Chinese, 帛度 (Bó Dù), meaning Textile Ruler, refers to an asterism consisting of 102 Herculis and 95 Her[12].Consequently, 102 Herculis itself is known as 帛度二 (Bó Dù èr, English: the Second Star of Textile Ruler.)

This star, together with 93 Her, 95 Her, and 109 Her, formed the now obsolete constellation of Cerberus.[13]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  3. 3.0 3.1 Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement 17: 371, doi:10.1086/190179, Bibcode1968ApJS...17..371L. 
  4. 4.0 4.1 4.2 4.3 4.4 Tetzlaff, N. et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode2011MNRAS.410..190T. 
  5. 5.0 5.1 Eggen, Olin J. (1961), "Space motions and distribution of the apparently bright B-type stars", Royal Observatory Bulletins 41: 245–287, Bibcode1961RGOB...41..245E. 
  6. 6.0 6.1 Bychkov, V. D. et al. (August 2003), "Catalogue of averaged stellar effective magnetic fields. I. Chemically peculiar A and B type stars", Astronomy and Astrophysics 407 (2): 631–642, doi:10.1051/0004-6361:20030741, Bibcode2003A&A...407..631B. 
  7. Lyubimkov, L. S. et al. (June 2004), "Surface abundances of light elements for a large sample of early B-type stars - III. An analysis of helium lines in spectra of 102 stars", Monthly Notices of the Royal Astronomical Society 351 (2): 745–767, doi:10.1111/j.1365-2966.2004.07825.x, Bibcode2004MNRAS.351..745L. 
  8. 8.0 8.1 Zorec, J. et al. (July 2009), "Fundamental parameters of B supergiants from the BCD system. I. Calibration of the (λ_1, D) parameters into Teff", Astronomy and Astrophysics 501 (1): 297–320, doi:10.1051/0004-6361/200811147, Bibcode2009A&A...501..297Z. 
  9. 9.0 9.1 Simón-Díaz, S. et al. (2017), "The IACOB project . III. New observational clues to understand macroturbulent broadening in massive O- and B-type stars", Astronomy and Astrophysics 597: A22, doi:10.1051/0004-6361/201628541, Bibcode2017A&A...597A..22S. 
  10. "102 Her". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=102+Her. 
  11. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  12. Ian Ridpath's Startales - Hercules
  13. Ian Ridpath's Star Tales - Cerberus