Observation data Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation
Pisces
Right ascension
01h 31m 29.01026s[1]
Declination
+15° 20′ 44.9685″[1]
Apparent magnitude (V)
+3.611[2](3.83 + 7.51)[3]
Characteristics
Spectral type
G7 IIIa[4]
U−B color index
+0.730[2]
B−V color index
+0.976[2]
Variable type
γ Cas
Astrometry
Radial velocity (Rv)
13.60±0.42[5] km/s
Proper motion (μ)
RA: +27.14[1] mas/yr Dec.: −2.64[1] mas/yr
Parallax (π)
9.33 ± 0.72 mas[1]
Distance
350 ± 30 ly (107 ± 8 pc)
Absolute magnitude (MV)
−1.52[6]
Orbit[7]
Period (P)
850.5±66.5 yr
Semi-major axis (a)
1.228±0.144″
Eccentricity (e)
0.469±0.053
Inclination (i)
58.5±2.5°
Longitude of the node (Ω)
32.8±2.0°
Periastron epoch (T)
2040.3±66.9
Argument of periastron (ω) (secondary)
86.9±4.0°
Details[5]
η Psc A
Mass
3.78±0.16M☉
Radius
26.48±2.15R☉
Luminosity
457 L☉
Surface gravity (log g)
2.20±0.14 cgs
Temperature
4,937±40 K
Metallicity [Fe/H]
−0.13±0.06 dex
Rotational velocity (v sin i)
8.4[8] km/s
Age
220±30 Myr
Other designations
Alpherg, η Psc, 99 Piscium, BD+14° 231, FK5 50, HD 9270, HIP 7097, HR 437, SAO 92484, WDS J01315+1521AB[9]
Database references
SIMBAD
data
Eta Piscium (η Piscium, abbreviated Eta Psc, η Psc) is a binary star and the brightest star in the constellation of Pisces, with an apparent visual magnitude of +3.6.[2] Based upon a measured annual parallax shift of 9.33 mas as seen from Earth,[1] it is located roughly 350 light-years distant from the Sun in the thin disk population of the Milky Way.[5]
The two components are designated Eta Piscium A (formally named Alpherg/ˈælfɜːrɡ/, the traditional name of the system)[10] and B.
^ abcdefCite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
^ abcdCite error: The named reference Oja1985 was invoked but never defined (see the help page).
^Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
^Cite error: The named reference Keenan1989 was invoked but never defined (see the help page).
^ abcCite error: The named reference Villaver2013 was invoked but never defined (see the help page).
^Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
^Cite error: The named reference Cvetkovic2010 was invoked but never defined (see the help page).
^Cite error: The named reference Auriere2015 was invoked but never defined (see the help page).
^Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
EtaPiscium (η Piscium, abbreviated Eta Psc, η Psc) is a binary star and the brightest star in the constellation of Pisces, with an apparent visual magnitude...
620 EtaPiscium Binary star system 3.63 3.55 Omicron Velorum Star 3.63 Beta Delphini Binary star system 3.82 3.5 Beta Doradus Star 3.87 3.480 Eta Aquilae...
consisting of Omicron Piscium, EtaPiscium, Rho Piscium, Pi Piscium and 104 Piscium. Consequently, the Chinese name for Omicron Piscium itself is 右更四 (Yòu...
identification number CXOU J013651.1+154547. Messier 74 is 1.5° east-northeast of EtaPiscium. This galaxy has the second-lowest Earth-surface brightness of any Messier...
the second brightest star in the constellation Pisces, between Eta and Alpha. Gamma Piscium moves across the sky at three-quarters of an arcsecond per year...
is a BY Draconis variable star with a variable star designation of BR Piscium. Its apparent magnitude varies between magnitude 8.93 and magnitude 9.03...
collapse or disk instability rather than core accretion. Epsilon Indi, 54 Piscium and Eta Telescopii, another stars orbited by brown dwarfs List of brown dwarfs...
dimmer stars (Zeta Leonis, Mu Leonis, Gamma Leonis, Epsilon Leonis, and Eta Leonis) have collectively been called 'the Sickle', which is an asterism...
Chandrasekhar, T.; Ashok, N. M. (1995). "Angular Diameter of Carbon Star Tx-Piscium from Lunar Occultation Observations in the Near Infrared". Journal of Astrophysics...
S2CID 11978733. Gull, Theodore R.; Damineli, Augusto (November 2009). "JD13 – Eta Carinae in the Context of the Most Massive Stars". Proceedings of the International...
(1998-10-01). "Fundamental stellar parameters for nearby visual binary stars: eta Cas, XI Boo, 70 OPH and 85 Peg. Helium abundance, age and mixing length parameter...
observations of the selected Algol-type binaries - IV. V799 Cassiopeiae, BX Piscium and HD 172189". Monthly Notices of the Royal Astronomical Society. 392...
Sun in the constellation Pisces, about 2° to the south of the star Delta Piscium, with a relatively high proper motion of 2.978″ annually along a position...
Juliette C.; Wright, Jason T.; Johnson, John Asher (2014), "The Nasa-Uc-Uh Eta-Earth Program. Iv. A Low-Mass Planet Orbiting an M Dwarf 3.6 Pc from Earth"...
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