51 Andromedae

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51 Andromedae
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 01h 37m 59.56s[1]
Declination +48° 37′ 41.6″[1]
Apparent magnitude (V) 3.57[2]
Spectral type K3-III[3]
U−B color index +1.44[2]
B−V color index +1.28[2]
Radial velocity (Rv) 18.41[4] km/s
Proper motion (μ) RA: 61.95 ± 0.17[1] mas/yr
Dec.: -112.15 ± 0.17[1] mas/yr
Parallax (π) 18.41 ± 0.18[1] mas
Distance 177 ± 2 ly
(54.3 ± 0.5 pc)
Absolute magnitude (MV) −0.04[5]
Mass 2.3[6] M
Radius 21.5 ± 0.9[7] R
Metallicity [Fe/H] 0.00[5] dex
Other designations
Nembus, υ Per, HD 9927, BD+47° 467, HIP 7607, HR 464, SAO 37375.
Database references

51 Andromedae (abbreviated 51 And), also named Nembus,[8] is the 5th brighest (4th magnitude) star in the constellation of Andromeda. It is an orange K-type giant star with an apparent magnitude of +3.59 and is approximately 177 light-years from the Earth.[1]


51 Andromedae is the star's Flamsteed designation. (Ptolemy included this star in Andromeda in the Almagest, but it was moved into Perseus by Johann Bayer, who designated it Upsilon Persei. Flamsteed moved it back, and the International Astronomical Union (IAU) made Flamsteed's 51 Andromedae its official designation in 1930.[9][10][11])

The star bore the traditional name Nembus[12][13] in Bayer's Uranometria (1603)[14] and Bode's star atlas Uranographia (1801).[15] In 2016, the IAU organized a Working Group on Star Names (WGSN)[16] to catalog and standardize proper names for stars. The WGSN approved the name Nembus for this star on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.[8]

In Chinese, 天大將軍 (Tiān Dà Jiāng Jūn), meaning Heaven's Great General, refers to an asterism consisting of 51 Andromedae, Gamma Andromedae, Phi Persei, 49 Andromedae, Chi Andromedae, Upsilon Andromedae, Tau Andromedae, 56 Andromedae, Beta Trianguli, Gamma Trianguli and Delta Trianguli.[17] Consequently, 51 Andromedae itself is known as 天大將軍三 (Tiān Dà Jiāng Jūn sān, English: the Third Star of Heaven's Great General.)[18]


  1. ^ a b c d e f van Leeuwen, F. (2007). "HIP 7607". Hipparcos, the New Reduction. Retrieved 2010-04-02. 
  2. ^ a b c 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. 
  3. ^ Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373. 
  4. ^ Maldonado, J.; Villaver, E.; Eiroa, C. (2013). "The metallicity signature of evolved stars with planets". Astronomy & Astrophysics. 554: A84. arXiv:1303.3418Freely accessible. Bibcode:2013A&A...554A..84M. doi:10.1051/0004-6361/201321082. 
  5. ^ a b Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics, 430: 303−311, arXiv:astro-ph/0409683Freely accessible, Bibcode:2005A&A...430..303C, doi:10.1051/0004-6361:20041440. 
  6. ^ Gondoin, P. (December 1999), "Evolution of X-ray activity and rotation on G-K giants", Astronomy and Astrophysics, 352: 217–227, Bibcode:1999A&A...352..217G 
  7. ^ Nordgren, Tyler E.; et al. (December 1999), "Stellar Angular Diameters of Late-Type Giants and Supergiants Measured with the Navy Prototype Optical Interferometer", The Astronomical Journal, 118 (6): 3032–3038, Bibcode:1999AJ....118.3032N, doi:10.1086/301114 
  8. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017. 
  9. ^ "Ephemerides – Report of Commissions", Transactions of the International Astronomical Union, 4: 20, 1932 
  10. ^ Allen, R. H. (1899). Star-names and Their Meanings. New York: G. E. Stechart. , p.34.
  11. ^ Wagman, Morton (2003) Lost Stars p.240, McDonald and Woodward, Blacksburg, Virginia. ISBN 0-939923-78-5.
  12. ^ Allen, R. H. (1899). Star-names and Their Meanings. New York: G. E. Stechart. , p.334.
  13. ^ p. 5, Astronomers' Stars, Patrick Moore, London, Routledge, 1987.
  14. ^ Scans of the plates of Uranometria by J. Bayer, 1603 Archived August 7, 2008, at the Wayback Machine. @Linda Hall Library
  15. ^ Scan of the plates of Uranographia by J.E. Bode, 1801 @Ian Ridpath's Star Tales
  16. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016. 
  17. ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  18. ^ (in Chinese) http://zh.wikipedia.org/zh-tw/%E5%A4%A9%E5%A4%A7%E5%B0%86%E5%86%9B%E4%B8%89

External links[edit]