Nu Cephei

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Nu Cephei
Observation data
Epoch J2000.0      Equinox J2000.0
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])
Spectral type A2Iab[2]
Apparent magnitude (U) 4.94[4]
Apparent magnitude (B) 4.81[4]
Apparent magnitude (J) 3.14[4]
Apparent magnitude (K) 2.85[4]
U−B color index +0.119[2]
B−V color index +0.518[2]
Variable type Alpha Cygni[3]
Radial velocity (Rv)−25.90[5] 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[6] pc
Absolute magnitude (MV)−6.82[7]
Mass15.4[6] M
Radius137[6] R
Diameter137[6] D
Luminosity102,000[6] L
Surface gravity (log g)1.35[2] cgs
Temperature8,800[2] K
Rotational velocity (v sin i)15[2] km/s
Age8[8] Myr
Other designations
10 Cephei, HD 207260, HR 8334, SAO 19624, FK5 1572, BD+60°2288, HIP 107418
Database references

Nu Cephei (ν Cephei) is a class A2, fourth-magnitude supergiant star in the constellation Cepheus. 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,[8] which includes stars such as μ Cephei and VV Cephei.[9] It began life as an approximately 20 M[6][8] star around eight million years ago. It has now exhausted its core hydrogen and expanded and cooled into a supergiant. Elemental abundance analyes 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.[8]

ν Cephei is currently about 15 times as massive as the sun, 190 times as large, and 100,000 times as luminous. 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. The brightness changes by at most a tenth of a magnitude.[3]


  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. arXiv:0708.1752. Bibcode 2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 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. arXiv:1207.0308. Bibcode 2012A&A...543A..80F. doi:10.1051/0004-6361/201219034.
  3. 3.0 3.1 3.2 Samus, N. N.Expression error: Unrecognized word "etal". (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 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.
  5. 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.
  6. 6.0 6.1 6.2 6.3 6.4 Lua error in Module:Citation/CS1 at line 925: attempt to concatenate local 'str' (a table value).
  7. 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.
  8. 8.0 8.1 8.2 8.3 Yüce, Kutluay (2005). "Spectral Analysis of 4 Lacertae and ν Cephei". Baltic Astronomy 14: 51. Bibcode 2005BaltA..14...51Y.
  9. Humphreys, R. M. (1978). "Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way". Astrophysical Journal 38: 309. Bibcode 1978ApJS...38..309H. doi:10.1086/190559.

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