OP Andromedae

OP Andromedae
	; The visual band light curve of OP Andromedae, adapted from Barksdale et al. (1984)
Observation data; Epoch J2000 Equinox J2000
Constellation	Andromeda
Right ascension	01h 36m 27.1998s
Declination	+48° 43′ 21.9998″}
Apparent magnitude (V)	6.27 - 6.41
Characteristics
Spectral type	K1III
Apparent magnitude (J)	3.794
Apparent magnitude (H)	3.165
Apparent magnitude (K)	2.914
B−V color index	1.2478
Variable type	RS CVn
Astrometry
Radial velocity (Rv)	−42.12±0.14 km/s
Proper motion (μ)	RA: −15.189±0.153 mas/yr ; Dec.: −17.663±0.148 mas/yr
Parallax (π)	6.3462 ± 0.0912 mas
Distance	514 ± 7 ly ; (158 ± 2 pc)
Absolute magnitude (MV)	0.37 ± 0.23
Details
Mass	1.5 – 3 M☉
Radius	16.1±2.2 R☉
Luminosity	128.825 L☉
Surface gravity (log g)	2.14 cgs
Temperature	4,490 K
Metallicity [Fe/H]	-0.10 dex
Rotational velocity (v sin i)	7.2 km/s
Other designations
	2MASS J01362720+4843221, BD+47° 460, HD 9746, HIP 7493, SAO 37351, PPM 44205, HR 454, TYC 3282-2270-1
Database references
SIMBAD	data

OP Andromedae is a variable star in the constellation Andromeda. Varying between magnitudes 6.27 and 6.41 over 2.36 days, it has been classified as an RS Canum Venaticorum variable, but there has not been any proof of binarity, yet.^[3] It is a red giant star with a spectral classification of K1III.

OP Andromedae is one of the few red giant stars where it was detected an overabundance of ⁷Li.^[6] The mechanism that enhances lithium in red giants is still unknown. It was proposed that those stars engulfed planets in the recent past; however, this theory was discarded since there is an overabundance of just one lithium isotope.^[7]

References

^ Barksdale, W. S.; Boyd, L. J.; Genet, R. M.; Chang, S.; Hall, D. S.; Ingvarsson, S. I. (1984). "Discovery that HR 454 is a Variable Star". Information Bulletin on Variable Stars. 2632.
^ ^a ^b ^c ^d ^e ^f 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.
^ ^a ^b ^c ^d N. N. Samus; O. V. Durlevich; et al. "OP And database entry". Combined General Catalog of Variable Stars (2017 ed.). CDS. Retrieved 2018-11-12.
^ ^a ^b ^c Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
^ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy & Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H.
^ ^a ^b ^c Balachandran, Suchitra C.; Fekel, Francis C.; Henry, Gregory W.; Uitenbroek, Han (2000). "Two K Giants with Supermeteoritic Lithium Abundances: HDE 233517 and HD 9746". The Astrophysical Journal. 542 (2): 978–88. Bibcode:2000ApJ...542..978B. CiteSeerX 10.1.1.36.1062. doi:10.1086/317055. S2CID 15952468.
^ ^a ^b ^c ^d ^e ^f ^g Takeda, Y.; Tajitsu, A. (August 2017). "On the observational characteristics of lithium-enhanced giant stars in comparison with normal red giants". Publications of the Astronomical Society of Japan. 69 (4): 978–88. arXiv:1706.02273. Bibcode:2017PASJ...69...74T. doi:10.1093/pasj/psx057. S2CID 119451146.

[Barksdale-1] Barksdale, W. S.; Boyd, L. J.; Genet, R. M.; Chang, S.; Hall, D. S.; Ingvarsson, S. I. (1984). "Discovery that HR 454 is a Variable Star". Information Bulletin on Variable Stars. 2632.

[Gaia-2] ^ ^a ^b ^c ^d ^e ^f 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.

[GCVS-3] N. N. Samus; O. V. Durlevich; et al. "OP And database entry". Combined General Catalog of Variable Stars (2017 ed.). CDS. Retrieved 2018-11-12.

[2MASS_Cat-4] Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.

[TYCHO-5] Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy & Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H.

[Balachandran_2000-6] Balachandran, Suchitra C.; Fekel, Francis C.; Henry, Gregory W.; Uitenbroek, Han (2000). "Two K Giants with Supermeteoritic Lithium Abundances: HDE 233517 and HD 9746". The Astrophysical Journal. 542 (2): 978–88. Bibcode:2000ApJ...542..978B. CiteSeerX 10.1.1.36.1062. doi:10.1086/317055. S2CID 15952468.

[Takeda2017-7] ^ ^a ^b ^c ^d ^e ^f ^g Takeda, Y.; Tajitsu, A. (August 2017). "On the observational characteristics of lithium-enhanced giant stars in comparison with normal red giants". Publications of the Astronomical Society of Japan. 69 (4): 978–88. arXiv:1706.02273. Bibcode:2017PASJ...69...74T. doi:10.1093/pasj/psx057. S2CID 119451146.

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Observation data Epoch J2000 Equinox J2000
The visual band light curve of OP Andromedae, adapted from Barksdale et al. (1984) ^[1]
Constellation	Andromeda
Right ascension	01^h 36^m 27.1998^s^[2]
Declination	+48° 43′ 21.9998″}^[2]
Apparent magnitude (V)	6.27 - 6.41^[3]
Characteristics
Spectral type	K1III^[3]
Apparent magnitude (J)	3.794^[4]
Apparent magnitude (H)	3.165^[4]
Apparent magnitude (K)	2.914^[4]
B−V color index	1.2478^[5]
Variable type	RS CVn^[3]
Astrometry

Radial velocity (R_v)	−42.12±0.14^[2] km/s
Proper motion (μ)	RA: −15.189±0.153^[2] mas/yr Dec.: −17.663±0.148^[2] mas/yr
Parallax (π)	6.3462 ± 0.0912 mas^[2]
Distance	514 ± 7 ly (158 ± 2 pc)
Absolute magnitude (M_V)	0.37 ± 0.23^[6]

Details

Mass	1.5 – 3^[7] `M`_☉
Radius	16.1±2.2^[6] `R`_☉
Luminosity	128.825^[7] `L`_☉
Surface gravity (log g)	2.14^[7] cgs
Temperature	4,490^[7] K
Metallicity [Fe/H]	-0.10^[7] dex
Rotational velocity (v sin i)	7.2^[7] km/s

Other designations
2MASS J01362720+4843221, BD+47° 460, HD 9746, HIP 7493, SAO 37351, PPM 44205, HR 454, TYC 3282-2270-1
Database references
SIMBAD	data