Zeta Andromedae

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ζ Andromedae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Andromeda
Right ascension 00h 47m 20.3254s[1]
Declination +24° 16′ 01.841″[1]
Apparent magnitude (V) 3.92 to 4.14[2]
Spectral type K1IIe[1]
U−B color index +0.90[3]
B−V color index +1.12[3]
R−I color index +0.59[3]
Variable type ELL/RS[2]
Radial velocity (Rv) −23.7 ± 0.9[1] km/s
Proper motion (μ) RA: −101.23[1] mas/yr
Dec.: −81.89[1] mas/yr
Parallax (π) 17.98 ± 0.83[1] mas
Distance 181 ± 8 ly
(56 ± 3 pc)
Absolute magnitude (MV) 0.3[4][dubious ]
Radius 16.0[5] R
Temperature 4,600[5] K
Rotation 17.77 days[5]
Rotational velocity (v sin i) 40[3] km/s
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.[1][6]
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 181 light years from Earth.[1]

Zeta Andromedae is an eclipsing spectroscopic binary whose primary is classified as an orange K-type bright giant with a mean apparent magnitude of +4.08. In addition to brightness variation due to eclipses, the system is also an RS Canum Venaticorum type or Beta Lyrae 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 optical.[3]

Multiple/double star designation: WDS 00473+2416[6]
Component Primary Right
Equinox J2000.0
Declination (δ)
Equinox J2000.0
Epoch of
to primary)
B A 00h 47m 20.2s +24° 16′ 33″[7] 1959 32.6 0° 15.3 Simbad
C A 00h 47m 15.2s +24° 15′ 03″[8] 1997 97.0 231° 13.6 Simbad
D A 00h 47m 08.9990s +24° 15′ 33.584″[9] 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.)[10]


  1. ^ a b c d e f g h i V* zet And -- Eclipsing binary of beta Lyr type, database entry, SIMBAD. Accessed on line August 29, 2008.
  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 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.
  4. ^ From apparent magnitude and parallax.
  5. ^ a b c 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 
  6. ^ a b Entry 00473+2416, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line August 29, 2008.
  7. ^ BD+23 106B -- Star in double system, database entry, SIMBAD. Accessed on line August 29, 2008.
  8. ^ BD+23 106C -- Star in double system, database entry, SIMBAD. Accessed on line August 29, 2008.
  9. ^ BD+23 106D -- Star in double system, database entry, SIMBAD. Accessed on line August 29, 2008.
  10. ^ (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]