Gamma Piscium

γ Piscium
	Location of γ Piscium (circled)
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Pisces
Right ascension	23h 17m 09.93749s
Declination	+03° 16′ 56.2380″
Apparent magnitude (V)	3.699
Characteristics
Spectral type	G8 III
U−B color index	+0.572
B−V color index	+0.924
Astrometry
Radial velocity (Rv)	-13.6 km/s
Proper motion (μ)	RA: 759.82 mas/yr ; Dec.: 17.77 mas/yr
Parallax (π)	23.64 ± 0.18 mas
Distance	138 ± 1 ly ; (42.3 ± 0.3 pc)
Absolute magnitude (MV)	0.68 ± 0.08
Details
Mass	1.11±0.29 M☉
Radius	11.28±0.10 R☉
Luminosity	62.7±3.3 L☉
Surface gravity (log g)	2.43 ± 0.06 cgs
Temperature	4833±62 K
Metallicity [Fe/H]	−0.51 dex
Age	4.58±3.10 Gyr
Other designations
	γ Piscium, 6 Piscium, BD+02°4648, FK5 878, GC 32415, HD 219615, HIP 114971, HR 8852, PPM 173938, SAO 128085, GC 32415, 2MASS J23170996+0316563
Database references
SIMBAD	data

Gamma Piscium (Gamma Psc, γ Piscium, γ Psc) is a star approximately 138 light years away from Earth,^[1] in the zodiac constellation of Pisces. It is a yellow star with a spectral type of G8 III, meaning it has a surface temperature of 4,833 K and is a giant star. It is slightly cooler than the Sun, yet it is 11^[3] solar radii in size and shines with the light of 63 Suns.^[3] At an apparent magnitude of 3.7,^[2] it is the second brightest star in the constellation Pisces, between Eta and Alpha. Once a white A2 star, it is 5.5 billion years old.^{[dubious – discuss]}

Gamma Piscium moves across the sky at three-quarters of an arcsecond per year, which at 138 light years corresponds to 153 kilometers per second. This suggests it is a visitor from another part of the Milky Way Galaxy; in astronomical terms, it will quickly leave the vicinity of the Sun. Its metallicity is only one-fourth that of the Sun, and visitors from outside the thin disk that composes the Milky Way tend to be metal-poor. Gamma Piscium is part of the asterism known as the "circlet of Pisces."^[7]

Naming[edit]

In Chinese, 霹靂 (Pī Lì), meaning Thunderbolt, refers to an asterism consisting of γ Piscium, β Piscium, θ Piscium, ι Piscium and ω Piscium. Consequently, the Chinese name for γ Piscium itself is 霹靂二 (Pī Lì èr, English: the Second Star of Thunderbolt.)^[8]

Planetary system[edit]

In 2021, a gas giant planet was detected by radial velocity method.^[9]

The planetary system^[9]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
Gamma Piscium b	>1.34^+0.02 _−0.31 M_J	1.32^+0.05 _−0.08	555.1^+6.0 _−2.5	0.204^+0.114 _−0.141	—	—

In fiction[edit]

In Frank Herbert's Dune series, Gamma Waiping (The Chinese name for Pisces) is the home system of Imperial House Corrino.^{[citation needed]}

References[edit]

^ ^a ^b ^c ^d ^e ^f van Leeuwen, Floor (13 August 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. eISSN 1432-0746. ISSN 0004-6361. Vizier catalog entry
^ ^a ^b ^c ^d Cousins, A. W. J. (1984), "Standardization of Broadband Photometry of Equatorial Standards", South African Astronomical Observatory Circulars, 8: 59, Bibcode:1984SAAOC...8...59C
^ ^a ^b ^c ^d ^e ^f ^g ^h Baines, Ellyn K.; et al. (2018). "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 155 (1). 30. arXiv:1712.08109. Bibcode:2018AJ....155...30B. doi:10.3847/1538-3881/aa9d8b. S2CID 119427037.
^ Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, Astronomisches Rechen-Institut Heidelberg, 35 (35): 1, Bibcode:1999VeARI..35....1W
^ ^a ^b ^c da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics, 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105, S2CID 9341088
^ "* gam Psc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 30, 2007.
^ "SPACE.com -- SpaceWatch -- Pisces Rising". Space.com. Archived from the original on July 13, 2010. Retrieved September 30, 2007.
^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 8 日
^ ^a ^b Teng, Huan-Yu; Sato, Bun'ei; Takarada, Takuya; Omiya, Masashi; Harakawa, Hiroki; Izumiura, Hideyuki; Kambe, Eiji; Takeda, Yoichi; Yoshida, Michitoshi; Itoh, Yoichi; Ando, Hiroyasu; Kokubo, Eiichiro (2022), "Regular radial velocity variations in nine G- and K-type giant stars: Eight planets and one planet candidate", Publications of the Astronomical Society of Japan, 74: 92–127, arXiv:2112.07169, doi:10.1093/pasj/psab112

[aaa474_2_653-1] ^ ^a ^b ^c ^d ^e ^f van Leeuwen, Floor (13 August 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. eISSN 1432-0746. ISSN 0004-6361. Vizier catalog entry

[saaoc8_59-2] Cousins, A. W. J. (1984), "Standardization of Broadband Photometry of Equatorial Standards", South African Astronomical Observatory Circulars, 8: 59, Bibcode:1984SAAOC...8...59C

[Baines2018-3] ^ ^a ^b ^c ^d ^e ^f ^g ^h Baines, Ellyn K.; et al. (2018). "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 155 (1). 30. arXiv:1712.08109. Bibcode:2018AJ....155...30B. doi:10.3847/1538-3881/aa9d8b. S2CID 119427037.

[scfs-4] Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, Astronomisches Rechen-Institut Heidelberg, 35 (35): 1, Bibcode:1999VeARI..35....1W

[aaa458_2_609-5] Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics, 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105, S2CID 9341088

[SIMBAD-6] "* gam Psc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 30, 2007.

[7] "SPACE.com -- SpaceWatch -- Pisces Rising". Space.com. Archived from the original on July 13, 2010. Retrieved September 30, 2007.

[8] (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 8 日

[Teng2021-9] Teng, Huan-Yu; Sato, Bun'ei; Takarada, Takuya; Omiya, Masashi; Harakawa, Hiroki; Izumiura, Hideyuki; Kambe, Eiji; Takeda, Yoichi; Yoshida, Michitoshi; Itoh, Yoichi; Ando, Hiroyasu; Kokubo, Eiichiro (2022), "Regular radial velocity variations in nine G- and K-type giant stars: Eight planets and one planet candidate", Publications of the Astronomical Society of Japan, 74: 92–127, arXiv:2112.07169, doi:10.1093/pasj/psab112

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Observation data Epoch J2000.0 Equinox J2000.0
Location of γ Piscium (circled)
Constellation	Pisces
Right ascension	23^h 17^m 09.93749^s^[1]
Declination	+03° 16′ 56.2380″^[1]
Apparent magnitude (V)	3.699^[2]
Characteristics
Spectral type	G8 III^[3]
U−B color index	+0.572 ^[2]
B−V color index	+0.924^[2]
Astrometry

Radial velocity (R_v)	-13.6^[4] km/s
Proper motion (μ)	RA: 759.82^[1] mas/yr Dec.: 17.77^[1] mas/yr
Parallax (π)	23.64 ± 0.18 mas^[1]
Distance	138 ± 1 ly (42.3 ± 0.3 pc)
Absolute magnitude (M_V)	0.68 ± 0.08^[5]

Details

Mass	1.11±0.29^[3] `M`_☉
Radius	11.28±0.10^[3] `R`_☉
Luminosity	62.7±3.3^[3] `L`_☉
Surface gravity (log g)	2.43 ± 0.06^[5] cgs
Temperature	4833±62^[3] K
Metallicity [Fe/H]	−0.51^[5] dex
Age	4.58±3.10^[3] Gyr

Other designations
γ Piscium, 6 Piscium, BD+02°4648, FK5 878, GC 32415, HD 219615, HIP 114971, HR 8852, PPM 173938, SAO 128085, GC 32415, 2MASS J23170996+0316563^[6]
Database references
SIMBAD	data