Epsilon Piscium[1]
Location of ε Piscium (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Pisces
Right ascension 01h 02m 56.60862s[2]
Declination +07° 53′ 24.4855″[2]
Apparent magnitude (V) 4.27[3]
Characteristics
Spectral type K0 III[4]
U−B color index +0.691[3]
B−V color index +0.952[4]
Astrometry
Radial velocity (Rv)+7.47±0.20[4] km/s
Proper motion (μ) RA: −80.17±0.19[2] mas/yr
Dec.: +25.59±0.14[2] mas/yr
Parallax (π)17.94 ± 0.21 mas[2]
Distance182 ± 2 ly
(55.7 ± 0.7 pc)
Absolute magnitude (MV)0.44[4]
Details
Mass2.27[4] M☉
Radius10.9±0.8[5] R☉
Luminosity67.6[6] L☉
Surface gravity (log g)2.99[7] cgs
Temperature4,814±40[6] K
Metallicity [Fe/H]−0.39[7] dex
Age2.56[6] Gyr
Other designations
ε Piscium, ε Psc, Epsilon Psc, 71 Piscium, BD+07 153, FK5 36, GC 1258, HD 6186, HIP 4906, HR 294, PPM 144204, SAO 109627.
Database references
SIMBADdata

Epsilon Piscium (Epsilon Psc, ε Piscium, ε Psc) is the Bayer designation for a star approximately 182 light-years (56 parsecs) away from the Earth,[2] in the constellation Pisces. It is a yellow-orange star of the G9 III or K0 III spectral type, meaning it has a surface temperature around 5,000 kelvins. This is a normal giant star, slightly cooler in surface temperature, yet brighter and larger than the Sun.[8] It is a suspected occultation double, with both stars having the same magnitude, separated by 0.25 arcsecond.[9]

Naming

In Chinese, 外屏 (Wài Píng), meaning Outer Fence, refers to an asterism consisting of ε Piscium, δ Piscium, ζ Piscium, μ Piscium, ν Piscium, ξ Piscium and α Piscium. Consequently, the Chinese name for ε Piscium itself is 外屏二 (Wài Píng èr, English: the Second Star of Outer Fence.)[10] In Japanese, 悠翔星 (Haruto-boshi), meaning "Soaring Forever Star," refers to the Japanese description of ε Piscium.

Planetary system

In 2021, a gas giant planetary candidate was detected by radial velocity method.[11]

The Epsilon Piscium planetary system[11]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b (unconfirmed) >0.77+0.16
−0.10 MJ		 0.88+0.11
−0.10		 255.3+2.1
−1.4		 0.278+0.122
−0.186		 — —

References

  1. ↑ "* eps Psc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 1, 2007.
  2. 1 2 3 4 5 6 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.
  3. 1 2 Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants", Monthly Notices of the Royal Astronomical Society, 172 (3): 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
  4. 1 2 3 4 5 Hekker, S.; et al. (August 2006), "Precise radial velocities of giant stars. I. Stable stars", Astronomy and Astrophysics, 454 (3): 943–949, arXiv:astro-ph/0604502, Bibcode:2006A&A...454..943H, doi:10.1051/0004-6361:20064946, S2CID 119529768
  5. ↑ Nordgren, Tyler E.; et al. (December 1999), "Stellar Angular Diameters of Late-Type Giants and Supergiants Measured with the Navy Prototype Optical Interferometer", The Astronomical Journal, 118 (6): 3032–3038, Bibcode:1999AJ....118.3032N, doi:10.1086/301114
  6. 1 2 3 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
  7. 1 2 Soubiran, C.; et al. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID 118362423.
  8. ↑ "Hipparcos Star Catalog Entry". Archived from the original on August 7, 2007. Retrieved October 1, 2007.
  9. ↑ "VizieR Detailed Page". Retrieved October 1, 2007.
  10. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日
  11. 1 2 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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