Epsilon Piscium

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. This is a giant star, slightly cooler in surface temperature, yet brighter and larger than the Sun.^[5] It is a suspected occultation double, with both stars having the same magnitude, separated by 0.25 arcsecond.^[8]

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]
Distance	182 ± 2 ly (55.7 ± 0.7 pc)
Absolute magnitude (MV)	0.44[4]
Details
Mass	2.27[4] M☉
Radius	11.39±0.19[5] R☉
Luminosity	63.92±1.33[5] L☉
Surface gravity (log g)	2.99[6] cgs
Temperature	4,834±32[5] K
Metallicity [Fe/H]	−0.39[6] dex
Age	2.56[7] 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
SIMBAD	data

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.)^[9] 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.^[10]

The Epsilon Piscium planetary system^[10]

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	—	—