Zeta Andromedae

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

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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.

[edit] Location

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 ascension (α) Equinox J2000.0	Declination (δ) Equinox J2000.0	Epoch of observed separation	Angular distance from primary	Position angle (relative to primary)	Apparent magnitude (V)	Database reference
B	A	00^h 47^m 20.2^s	+24° 16′ 33″^[7]	1959	32.6″	0°	15.3	Simbad
C	A	00^h 47^m 15.2^s	+24° 15′ 03″^[8]	1997	97.0″	231°	13.6	Simbad
D	A	00^h 47^m 08.9990^s	+24° 15′ 33.584″^[9]	2006	155.5″	260°	10.80	Simbad

^ ^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.
^ ^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.
^ ^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.
^ From apparent magnitude and parallax.
^ ^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
^ ^a ^b Entry 00473+2416, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line August 29, 2008.
^ BD+23 106B -- Star in double system, database entry, SIMBAD. Accessed on line August 29, 2008.
^ BD+23 106C -- Star in double system, database entry, SIMBAD. Accessed on line August 29, 2008.
^ BD+23 106D -- Star in double system, database entry, SIMBAD. Accessed on line August 29, 2008.

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Observation data Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Andromeda
Right ascension	00^h 47^m 20.3254^s^[1]
Declination	+24° 16′ 01.841″^[1]
Apparent magnitude (V)	3.92 to 4.14^[2]
Characteristics
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]
Astrometry

Radial velocity (R_v)	−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 (M_V)	0.3^[4]

Details

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
SIMBAD	data