19 Cephei

19 Cephei is a supergiant star in the northern circumpolar constellation of Cepheus. It has a spectral class of O9 and is a member of Cep OB2, an OB association of massive stars located about 615 parsecs (2,010 ly) from the Sun.

19 Cep
Location of 19 Cephei (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Cepheus
Right ascension  22h 05m 08.78995s[1]
Declination +62° 16′ 47.3301″[1]
Apparent magnitude (V) 5.08[2]
Characteristics
Spectral type O9Ib[3]
U−B color index −0.91[2]
B−V color index +0.06[2]
Astrometry
Radial velocity (Rv)−12.8±0.9[4] km/s
Proper motion (μ) RA: −1.16[1] mas/yr
Dec.: −2.96[1] mas/yr
Parallax (π)1.58 ± 0.19[1] mas
Distance1,200[5] pc
Absolute magnitude (MV)−5.45[6]
Details
Mass20[7] M☉
Radius17.0[3] R☉
Luminosity224,000[3] L☉
Surface gravity (log g)3.40±0.08[8] cgs
Temperature32,983±1,428[8] K
Metallicity [Fe/H]0.06±0.08[8] dex
Rotational velocity (v sin i)48[3] km/s
Other designations
19 Cep, BD+61°2246, HD 209975, HIP 109017, HR 8428, SAO 19849.
Database references
SIMBADdata

The spectrum of 19 Cephei shows line profile variability on an hourly and daily timescale. This is thought to be due to the changes in the stellar wind.[3]

Double star catalogues list several companions for 19 Cephei. The Washington Double Star Catalog describes four companions: 11th magnitude stars 20" and 56" away, and two 15th magnitude stars 4-5" away.[9] The Catalog of Components of Double and Multiple Stars gives only the two 11th magnitude stars.[10]

A scattered cluster of faint stars has been detected associated with 19 Cephei. The brightest likely members apart from 19 Cep itself are 10th magnitude stars.[11]

References
  1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357Vizier catalog entry
  2. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M
  3. Martins, F.; Marcolino, W.; Hillier, D. J.; Donati, J.-F.; Bouret, J.-C. (2015). "Radial dependence of line profile variability in seven O9-B0.5 stars". Astronomy & Astrophysics. 574: A142. arXiv:1409.5057. Bibcode:2015A&A...574A.142M. doi:10.1051/0004-6361/201423882.
  4. Gontcharov, G. A. (November 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.
  5. Aldoretta, E. J.; Caballero-Nieves, S. M.; Gies, D. R.; Nelan, E. P.; Wallace, D. J.; Hartkopf, W. I.; Henry, T. J.; Jao, W.-C.; Maíz Apellániz, J.; Mason, B. D.; Moffat, A. F. J.; Norris, R. P.; Richardson, N. D.; Williams, S. J. (2015). "The Multiplicity of Massive Stars: A High Angular Resolution Survey with the Guidance Sensor". The Astronomical Journal. 149: 26. arXiv:1410.0021. Bibcode:2015AJ....149...26A. doi:10.1088/0004-6256/149/1/26.
  6. Puls, J.; Markova, N.; Scuderi, S.; Stanghellini, C.; Taranova, O. G.; Burnley, A. W.; Howarth, I. D. (2006). "Bright OB stars in the Galaxy. III. Constraints on the radial stratification of the clumping factor in hot star winds from a combined Hα, IR and radio analysis". Astronomy and Astrophysics. 454 (2): 625. arXiv:astro-ph/0604372. Bibcode:2006A&A...454..625P. doi:10.1051/0004-6361:20065073.
  7. Villamariz, M. R.; et al. (June 2002), "Chemical composition of Galactic OB stars I. CNO abundances in O9 stars", Astronomy and Astrophysics, 388 (3): 940–956, arXiv:astro-ph/0204209, Bibcode:2002A&A...388..940V, doi:10.1051/0004-6361:20020400
  8. Prugniel, P.; Vauglin, I.; Koleva, M. (2011). "The atmospheric parameters and spectral interpolator for the MILES stars". Astronomy & Astrophysics. 531: A165. arXiv:1104.4952. Bibcode:2011A&A...531A.165P. doi:10.1051/0004-6361/201116769.
  9. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
  10. Dommanget, J.; Nys, O. (1994). "Catalogue des composantes d'etoiles doubles et multiples (CCDM) premiere edition - Catalogue of the components of double and multiple stars (CCDM) first edition". Com. de l'Observ. Royal de Belgique. 115: 1. Bibcode:1994CoORB.115....1D.
  11. Kharchenko, N. V.; Piskunov, A. E.; Röser, S.; Schilbach, E.; Scholz, R.-D. (2005). "109 new Galactic open clusters". Astronomy and Astrophysics. 440: 403. arXiv:astro-ph/0505019. Bibcode:2005A&A...440..403K. doi:10.1051/0004-6361:20052740.
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