Zeta Andromedae

ζ Andromedae
Observation data; Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Andromeda
Right ascension	00h 47m 20.32547s
Declination	+24° 16′ 01.8408″
Apparent magnitude (V)	3.92 to 4.14
Characteristics
Spectral type	K1III + KV
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)	−24.43 ± 0.1 km/s
Proper motion (μ)	RA: −101.17 mas/yr ; Dec.: −81.77 mas/yr
Parallax (π)	17.24 ± 0.26 mas
Distance	189 ± 3 ly ; (58.0 ± 0.9 pc)
Absolute magnitude (MV)	+0.14
Orbit
Period (P)	17.769426
Semi-major axis (a)	2.7 R*
Eccentricity (e)	0.0
Inclination (i)	65 ± 5°
Details
Aa
Mass	2.6 ± 0.4 M☉
Radius	15.9 ± 0.8 R☉
Luminosity	95.5 L☉
Surface gravity (log g)	2.8 cgs
Temperature	4,665 ± 140 K
Metallicity [Fe/H]	−0.30 dex
Rotation	17.77 days
Rotational velocity (v sin i)	41.4 ± 0.2 km/s
Ab
Mass	0.75 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
SIMBAD	data

Coordinates: 00^h 47^m 20.3254^s, +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, and its spectrum shows strong and variable Ca II H and K lines.^[3] The orbital period of the binary is 17.77 days.

Location[]

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

Diagram of Andromeda constellation

Direct imaging[]

The primary component of this binary system, Zeta Andromedae Aa, is one of the few stars who has been imaged directly using Doppler imaging and long-baseline infrared interferometry. With direct imaging we can recover additional information about this star.

Additional star parameters^[8]
Parameter	Value
Oblateness	1.060 ± 0.011
Polar radius	15.0 ± 0.8 `R`_☉
Axis Inclination^[a]	70.0 ± 2.8 °
Pole angle^[b]	126 ± 1.9 °

Direct imaging also allowed observation of starspots, (the analogue to sunspots), on this star, and their asymmetric distribution showed that the magnetic field of the star is generated by a mechanism different from the solar dynamo.^[8] A Sun-like differential rotation of the star was observed instead.^[3]

Visual companions[]

The WDS lists more than one visual companion to the eclipsing binary.^[4] B has common proper motion with A. C is probably only a line-of-sight companion that has no physical association. The parallax of the D component has been measured by Gaia and the distance of this star is much different.^[9]

Multiple/double star designation: WDS 00473+2416^[10]
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″	1959	32.6″	0°	15.3
C	A	00^h 47^m 15.2^s	+24° 15′ 03″	1997	97.0″	231°	13.6
D	A	00^h 47^m 09.0^s	+24° 15′ 33″	2006	155.5″	260°	10.80	SIMBAD

Naming[]

In Chinese, 奎宿 (Kuí Sù), meaning Legs (asterism), refers to an asterism consisting of ζ Andromedae, η Andromedae, , ε Andromedae, δ Andromedae, π Andromedae, ν Andromedae, μ Andromedae, β Andromedae, σ Piscium, τ Piscium, , υ Piscium, φ Piscium, χ Piscium and ψ¹ Piscium. Consequently, the Chinese name for ζ Andromedae itself is 奎宿二 (Kuí Sù èr, English: the Second Star of Legs.)^[11]

Notes[]

^ Azimuthal angle between the rotational axis and our line of sight
^ Longitudinal angle between the north pole and the East direction

References[]

^ Jump up to: ^a ^b ^c ^d ^e 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. S2CID 18759600.
^ Jump up to: ^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.
^ Jump up to: ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k 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. arXiv:1301.0445. Bibcode:2007A&A...463.1071K. doi:10.1051/0004-6361:20065982.
^ Jump up to: ^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.
^ 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/0404219. Bibcode:2004MNRAS.349.1069K. doi:10.1111/j.1365-2966.2004.07588.x. S2CID 15290475.
^ Jump up to: ^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:1002.4201. Bibcode:2010A&A...515A..14K. doi:10.1051/0004-6361/200913736. S2CID 118683792.
^ 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
^ Jump up to: ^a ^b Roettenbacher, R.M.; Monnier, J.D.; Korhonen, H.; Aarnio, A.N.; Baron, F.; Che, X.; Harmon, R.O.; Kővári, Zs.; Kraus, S.; Schaefer, G.H.; Torres, G.; Zhao, M.; Ten Brummelaar, T.A.; Sturmann, J.; Sturmann, L. (2016). "No Sun-like dynamo on the active star ζ Andromedae from starspot asymmetry". Nature. 533 (7602): 217–220. arXiv:1709.10107. Bibcode:2016Natur.533..217R. doi:10.1038/nature17444. PMID 27144357. S2CID 4466687.
^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
^ 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.
^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日

External links[]

Zeta Andromedae at Alcyone Software's Star Data Pages
Image ζ Andromedae
Rachael Roettenbacher, "How the face of a distant star reveals our place in the cosmos," Aeon Magazine [retrieved July 27, 2016]

[axis-9] Azimuthal angle between the rotational axis and our line of sight

[pole-10] Longitudinal angle between the north pole and the East direction

[hipparcos-1] Jump up to: ^a ^b ^c ^d ^e 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. S2CID 18759600.

[gcvs1-2] Jump up to: ^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.

[kovari-3] Jump up to: ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k 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. arXiv:1301.0445. Bibcode:2007A&A...463.1071K. doi:10.1051/0004-6361:20065982.

[bsc2-4] Jump up to: ^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.

[karatas-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/0404219. Bibcode:2004MNRAS.349.1069K. doi:10.1111/j.1365-2966.2004.07588.x. S2CID 15290475.

[korhonen-6] Jump up to: ^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:1002.4201. Bibcode:2010A&A...515A..14K. doi:10.1051/0004-6361/200913736. S2CID 118683792.

[aar17_3_251-7] 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

[roettenbacher-8] Jump up to: ^a ^b Roettenbacher, R.M.; Monnier, J.D.; Korhonen, H.; Aarnio, A.N.; Baron, F.; Che, X.; Harmon, R.O.; Kővári, Zs.; Kraus, S.; Schaefer, G.H.; Torres, G.; Zhao, M.; Ten Brummelaar, T.A.; Sturmann, J.; Sturmann, L. (2016). "No Sun-like dynamo on the active star ζ Andromedae from starspot asymmetry". Nature. 533 (7602): 217–220. arXiv:1709.10107. Bibcode:2016Natur.533..217R. doi:10.1038/nature17444. PMID 27144357. S2CID 4466687.

[gaia-11] Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.

[wds-12] 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.

[aeea-13] (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日

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Observation data Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Andromeda
Right ascension	00^h 47^m 20.32547^s^[1]
Declination	+24° 16′ 01.8408″^[1]
Apparent magnitude (V)	3.92 to 4.14^[2]
Characteristics
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]
Astrometry

Radial velocity (R_v)	−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 (M_V)	+0.14^[3]

Orbit^[3]
Period (P)	17.769426
Semi-major axis (a)	2.7 R_*
Eccentricity (e)	0.0
Inclination (i)	65 ± 5°
Details
Aa
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
Ab
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
SIMBAD	data