Zeta Andromedae

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ζ Andromedae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Andromeda
Right ascension 00h 47m 20.32547s[1]
Declination +24° 16′ 01.8408″[1]
Apparent magnitude (V) 3.92 to 4.14[2]
Spectral type K1III + KV[3]
U−B color index +0.90[4]
B−V color index +1.12[4]
R−I color index +0.59[4]
Variable type ELL/RS[2]
Radial velocity (Rv) −24.43 ± 0.1[5] km/s
Proper motion (μ) RA: −101.17[1] mas/yr
Dec.: −81.77[1] mas/yr
Parallax (π) 17.24 ± 0.26[1] mas
Distance 189 ± 3 ly
(58.0 ± 0.9 pc)
Absolute magnitude (MV) +0.14[3]
Period (P) 17.769426
Semi-major axis (a) 2.7 R*
Eccentricity (e) 0.0
Inclination (i) 65 ± 5°
Mass 2.6 ± 0.4[3] M
Radius 15.9 ± 0.8[6] R
Luminosity 95.5[3] L
Surface gravity (log g) 2.8[3] cgs
Temperature 4,665 ± 140[6] K
Metallicity [Fe/H] −0.30[3] dex
Rotation 17.77 days[7]
Rotational velocity (v sin i) 41.4 ± 0.2[3] km/s
Mass 0.75[3] M
Other designations
ζ And, Zeta Andromedae, Zeta And, 34 Andromedae, 34 And, BD+23°106, CCDM J00473+2416A, FK5 27, GC 940, HD 4502, HIP 3693, HR 215, IDS 00421+2344 A, PPM 90149, SAO 74267, WDS 00473+2416A.
Database references

Coordinates: Sky map 00h 47m 20.3254s, +24° 16′ 01.841″

Zeta Andromedae (Zeta And, ζ Andromedae, ζ And) is a star system in the constellation Andromeda. It is approximately 189 light years from Earth.

Zeta Andromedae is a spectroscopic binary whose primary is classified as an orange K-type giant with a mean apparent magnitude of +4.08. In addition to brightness variation due to the ellipsoidal shape of the giant primary star, the system is also an RS Canum Venaticorum type variable star. Its brightness varies from magnitude +3.92 to +4.14 with a period of 17.77 days. The orbital period of the binary is 17.77 days.


This star's location in the constellation Andromeda can be seen in the following diagram:

Diagram of Andromeda constellation


A number of visual companions to the eclipsing binary have been observed. B has common proper motion with A, but C and D are probably only line-of-sight companions that have no physical association.[4]

Multiple/double star designation: WDS 00473+2416[8]
Component Primary Right
Equinox J2000.0
Declination (δ)
Equinox J2000.0
Epoch of
to primary)
B A 00h 47m 20.2s +24° 16′ 33″[9] 1959 32.6 0° 15.3 SIMBAD
C A 00h 47m 15.2s +24° 15′ 03″[10] 1997 97.0 231° 13.6 SIMBAD
D A 00h 47m 08.9990s +24° 15′ 33.584″[11] 2006 155.5 260° 10.80 SIMBAD


In Chinese, 奎宿 (Kuí Sù), meaning Legs (asterism), refers to an asterism consisting of ζ Andromedae, η Andromedae, 65 Piscium, ε Andromedae, δ Andromedae, π Andromedae, ν Andromedae, μ Andromedae, β Andromedae, σ Piscium, τ Piscium, 91 Piscium, υ Piscium, φ Piscium, χ Piscium and ψ¹ Piscium. Consequently, ζ Andromedae itself is known as 奎宿二 (Kuí Sù èr, English: the Second Star of Legs.)[12]


  1. ^ a b c d e Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ a b zet And, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line August 29, 2008.
  3. ^ a b c d e f g h Kővári, Zs.; Bartus, J.; Strassmeier, K. G.; Oláh, K.; Weber, M.; Rice, J. B.; Washuettl, A. (2007). "Doppler imaging of stellar surface structure. XXIII. The ellipsoidal K giant binary ζ Andromedae". Astronomy and Astrophysics. 463 (3): 1071. Bibcode:2007A&A...463.1071K. doi:10.1051/0004-6361:20065982. 
  4. ^ a b c d HR 215, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line August 29, 2008.
  5. ^ Karataş, Y.; Bilir, S.; Eker, Z.; Demircan, O. (2004). "Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution". Monthly Notices of the Royal Astronomical Society. 349 (3): 1069. arXiv:astro-ph/0404219Freely accessible. Bibcode:2004MNRAS.349.1069K. doi:10.1111/j.1365-2966.2004.07588.x. 
  6. ^ a b Korhonen, H.; Wittkowski, M.; Kovári, Zs.; Granzer, Th.; Hackman, T.; Strassmeier, K. G. (2010). "Ellipsoidal primary of the RS CVn binary ζ Andromedae . Investigation using high-resolution spectroscopy and optical interferometry". Astronomy and Astrophysics. 515: A14. arXiv:1002.4201Freely accessible. Bibcode:2010A&A...515A..14K. doi:10.1051/0004-6361/200913736. 
  7. ^ Strassmeier, Klaus G. (September 2009), "Starspots", The Astronomy and Astrophysics Review, 17 (3): 251–308, Bibcode:2009A&ARv..17..251S, doi:10.1007/s00159-009-0020-6 
  8. ^ Entry 00473+2416, The Washington Double Star Catalog Archived April 12, 2008, at the Wayback Machine., United States Naval Observatory. Accessed on line August 29, 2008.
  9. ^ BD+23 106B -- Star in double system, database entry, SIMBAD. Accessed on line August 29, 2008.
  10. ^ BD+23 106C -- Star in double system, database entry, SIMBAD. Accessed on line August 29, 2008.
  11. ^ BD+23 106D -- Star in double system, database entry, SIMBAD. Accessed on line August 29, 2008.
  12. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日

External links[edit]