Psi1 Piscium

For other stars with this Bayer designation, see ψ Piscium.

Psi¹ Piscium (Psi¹ Psc, ψ¹ Piscium, ψ¹ Psc) is a binary star in the constellation Pisces. It is approximately 280 light years from Earth, based on its parallax.^[1]

ψ¹ Piscium

Location of ψ1 Piscium (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Pisecs
ψ1 Psc A
Right ascension	01h 05m 40.95527s[1]
Declination	+21° 28′ 23.4489″[1]
Apparent magnitude (V)	5.273[2]
ψ1 Psc B
Right ascension	01h 05m 41.71111s[3]
Declination	+21° 27′ 55.6120″[3]
Apparent magnitude (V)	5.455[2]
Characteristics
ψ1 Psc A
Spectral type	A1V + A4V[4]
U−B color index	−0.12[5]
B−V color index	−0.04[5]
ψ1 Psc B
Spectral type	A0Vn[6]
U−B color index	−0.17[5]
B−V color index	−0.06[5]
Astrometry
ψ1 Psc A
Radial velocity (Rv)	−3.90±2.9[7] km/s
Proper motion (μ)	RA: 44.49[1] mas/yr Dec.: −14.82[1] mas/yr
Parallax (π)	11.86±0.68 mas[1]
Distance	280 ± 20 ly (84 ± 5 pc)
Absolute magnitude (MV)	+0.71[8]
ψ1 Psc B
Radial velocity (Rv)	−7.20±3.6[9] km/s
Proper motion (μ)	RA: 54.952[3] mas/yr Dec.: −15.938[3] mas/yr
Parallax (π)	11.3778±0.0506 mas[3]
Distance	287 ± 1 ly (87.9 ± 0.4 pc)
Absolute magnitude (MV)	+0.89[8]
Orbit[4]
Primary	ψ1 Psc Aa
Companion	ψ1 Psc Ab
Period (P)	14.44±0.26 yr
Semi-major axis (a)	114.3±1.7″
Eccentricity (e)	0.519±0.027
Inclination (i)	77.43±0.81°
Longitude of the node (Ω)	134.8±1.2°
Periastron epoch (T)	B 2007.512±0.041
Argument of periastron (ω) (secondary)	305.4±2.3°
Details
ψ1 Psc Aa
Mass	2.2[10] M☉
ψ1 Psc Ab
Mass	1.7[10] M☉
Details
ψ1 Psc B
Mass	2.6[3] M☉
Radius	2.2[3] R☉
Luminosity	57[3] L☉
Surface gravity (log g)	4.04[3] cgs
Temperature	10,694[3] K
Rotational velocity (v sin i)	250[11] km/s
Age	210[3] Myr
Other designations
ψ1 Psc, 74 Psc, ADS 899 AB, CCDM J01057+2128
ψ1 Psc A: BD+20°156, HD 6456, HIP 5131, HR 310, SAO 74482
ψ1 Psc B: BD+20°157, HD 6457, HIP 5132, HR 311, SAO 74483
Database references
SIMBAD	ψ1 Psc A
	ψ1 Psc B

The two components of Psi¹ Piscium are both A-type main-sequence stars.^[4][6] The primary has an apparent magnitude of 5.273, while the secondary is slightly dimmer, with an apparent magnitude of 5.455.^[2] The primary itself is a close binary, with two A-type stars that orbit each other every 14.44 years.^[4]

Psi¹ Piscium is moving through the Galaxy at a speed of 22.5 km/s relative to the Sun. Its projected Galactic orbit carries it between 22,800 and 24,300 light years from the center of the Galaxy.^[12]

Naming

In Chinese, 奎宿 (Kuí Sù), meaning Legs (asterism), refers to an asterism consisting of refers to an asterism consisting of ψ¹ Piscium, η Andromedae, 65 Piscium, ζ Andromedae, ε Andromedae, δ Andromedae, π Andromedae, ν Andromedae, μ Andromedae, β Andromedae, τ Piscium, 91 Piscium, υ Piscium, φ Piscium and χ Piscium. Consequently, the Chinese name for ψ¹ Piscium itself is 奎宿十六 (Kuí Sù shíliù, English: the Sixteenth Star of Legs.)^[13]