Astronomy:Nu Cephei

From HandWiki
Short description: Star in the constellation Cepheus
ν Cephei
Location of ν Cephei (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cepheus
Right ascension  21h 45m 26.925s[1]
Declination +61° 07′ 14.90″[1]
Apparent magnitude (V) 4.289[2] (4.25 - 4.35[3])
Characteristics
Evolutionary stage Blue supergiant[4]
Spectral type A2Iab[2]
Apparent magnitude (U) 4.94[5]
Apparent magnitude (B) 4.81[5]
Apparent magnitude (J) 3.14[5]
Apparent magnitude (K) 2.85[5]
U−B color index +0.119[2]
B−V color index +0.518[2]
Variable type Alpha Cygni[3]
Astrometry
Radial velocity (Rv)−25.90[6] km/s
Proper motion (μ) RA: −3.74 ± 0.13[1] mas/yr
Dec.: −2.10 ± 0.12[1] mas/yr
Parallax (π)0.48 ± 0.14[1] mas
Distance1,450[7] pc
Absolute magnitude (MV)−6.82[8]
Details
Mass15.4[7] M☉
Radius137[7] R☉
Luminosity102,000[7] L☉
Surface gravity (log g)1.35[2] cgs
Temperature8,800[2] K
Rotational velocity (v sin i)15[2] km/s
Age8[4] Myr
Other designations
10 Cephei, HD 207260, HR 8334, SAO 19624, FK5 1572, BD+60°2288, HIP 107418
Database references
SIMBADdata
A light curve for Nu Cephei, plotted from TESS data,[9]

Nu Cephei (ν Cephei) is a class A2, fourth-magnitude blue supergiant star in the constellation Cepheus, visible to the naked eye. It is a white pulsating α Cygni variable star located about 4,700 light-years from Earth.

ν Cephei is a member of the Cepheus OB2 stellar association,[4] which includes stars such as μ Cephei and VV Cephei.[10] It began life as an approximately 20 M☉[7][4] star around eight million years ago. It has now exhausted its core hydrogen and expanded and cooled into a supergiant. Elemental abundance analyses indicate that it has not yet spent time as a red supergiant, which would have brought about convection of fusion products to the surface in a Dredge-up.[4]

ν Cephei is currently about 15 times as massive as the sun, 137 times as large, and 100,000 times as luminous.[7] Its large size and luminosity cause it to be somewhat unstable and produce irregular pulsations. This is a common feature of class A and B supergiants, which are grouped as α Cygni variable stars. Variability was first reported by Helmut Abt in 1957.[11] The brightness changes by at most a tenth of a magnitude.[3] A variety of values for the variability period have been published, including 5 to 10 days,[12] 7.6 days[13][11] and 90 days.[14]

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. Vizier catalog entry
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Firnstein, M.; Przybilla, N. (2012). "Quantitative spectroscopy of Galactic BA-type supergiants. I. Atmospheric parameters". Astronomy & Astrophysics 543: A80. doi:10.1051/0004-6361/201219034. Bibcode: 2012A&A...543A..80F. 
  3. ↑ 3.0 3.1 3.2 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. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 Yüce, Kutluay (2005). "Spectral Analysis of 4 Lacertae and ν Cephei". Baltic Astronomy 14: 51. Bibcode: 2005BaltA..14...51Y. 
  5. ↑ 5.0 5.1 5.2 5.3 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues 2237. Bibcode: 2002yCat.2237....0D. 
  6. ↑ 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. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 Firnstein, Markus (2010). Quantitative Spectroscopy of Galactic BA-Type Supergiants (Ph.D.). Erlangen, Nürnberg, Univ.
  8. ↑ Verdugo, E.; Talavera, A.; Gómez De Castro, A. I. (1999). "Understanding A-type supergiants. II. Atmospheric parameters and rotational velocities of Galactic A-type supergiants". Astronomy and Astrophysics 346: 819. Bibcode: 1999A&A...346..819V. 
  9. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  10. ↑ Humphreys, R. M. (1978). "Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way". Astrophysical Journal 38: 309. doi:10.1086/190559. Bibcode: 1978ApJS...38..309H. 
  11. ↑ 11.0 11.1 Abt, Helmut A. (July 1957). "The Variability of Supergiants". Astrophysical Journal 126: 138–151. doi:10.1086/146379. Bibcode: 1957ApJ...126..138A. 
  12. ↑ Percy, J. R.; Welch, D. L. (August 1983). "Photometric variability of B- and A-type supergiants". Publications of the Astronomical Society of the Pacific 95: 491–505. doi:10.1086/131198. Bibcode: 1983PASP...95..491P. 
  13. ↑ Buscombe, W. (June 1974). "Variations in the spectra of A-type supergiants". The Observatory 94: 120–122. Bibcode: 1974Obs....94..120B. 
  14. ↑ "nu. Cep". AAVSO. https://www.aavso.org/vsx/index.php?view=detail.top&oid=9070. 



Retrieved from "https://handwiki.org/wiki/index.php?title=Astronomy:Nu_Cephei&oldid=3931396"