Eta Piscis Austrini

η Piscis Austrini
Location of η Piscis Austrini (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Piscis Austrinus
A
Right ascension 22h 00m 50.22454s[1]
Declination −28° 27′ 13.4587″[1]
Apparent magnitude (V) 5.742[2]
B
Right ascension 22h 00m 50.34936s[3]
Declination −28° 27′ 14.1460″[3]
Apparent magnitude (V) 6.825[2]
Characteristics
Spectral type B6 III shell + B8.5 V[4]
U−B color index −0.30[5]
B−V color index −0.10[5]
Variable type suspected[6]
Astrometry
Absolute magnitude (MV)−1.53[7]
A
Proper motion (μ) RA: +15.289[1] mas/yr
Dec.: −0.096[1] mas/yr
Parallax (π)3.8087 ± 0.0932 mas[1]
Distance860 ± 20 ly
(263 ± 6 pc)
B
Proper motion (μ) RA: +17.554[3] mas/yr
Dec.: −1.229[3] mas/yr
Parallax (π)4.5342 ± 0.3306 mas[3]
Distance720 ± 50 ly
(220 ± 20 pc)
Details
η PsA A
Mass4.01±0.18[8] M☉
Luminosity881[9] L☉
Surface gravity (log g)3.48[9] cgs
Temperature12,310[9] K
Rotational velocity (v sin i)320[9] km/s
Age115[10] Myr
η PsA B
Mass3.6[11] M☉
Surface gravity (log g)4.17[11] cgs
Temperature14,144[11] K
Metallicity [Fe/H]−0.21[11] dex
Other designations
η PsA, 12 Piscis Austrini, CPD−29° 6659, HD 209014, HIP 108661, HR 8386, SAO 190822, WDS J22008-2827AB[12]
Database references
SIMBADdata

Eta Piscis Austrini (η Piscis Austrini) is binary star[2] system in the southern constellation of Piscis Austrinus. As of 2000, the two components had an angular separation of 1.818 arc seconds along a position angle of 113.4°. The pair have a combined apparent visual magnitude of +5.43,[5] which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 3.99 mas as seen from the Earth,[13] the system is located roughly 820 light years from the Sun.

Although not catalogued formally as a variable star, brightness changes between magnitude 5,33 and 5.44 have been widely reported.[6][14] The type of variability is thought to be related to its rapid rotation and a surrounding shell, and is tentatively given as a combination of a Be star and Maia variable.[15]

The magnitude 5.7 primary, component A,[2] is a blue-white hued Be star[10] with a stellar classification B6 III.[4] At 115 million years old,[10] the star is spinning rapidly with a projected rotational velocity of 265.[8] It has an estimated four times the mass of the Sun and is radiating 604 times the solar luminosity at an effective temperature of 11,272 K.[8] The secondary, component B, has a visual magnitude of 6.8[2] and a spectral class of B8.5 V.[4]

Eta Piscis Austrini is moving through the Galaxy at a speed of 11.3 km/s relative to the Sun. Its projected Galactic orbit carries it between 23,600 and 30,800 light years from the center of the Galaxy.[16][unreliable source?]

  1. ^ a b c d e Cite error: The named reference dr3a was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference Fabricius2000 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference dr3b was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Corbally1984 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Feinstein1979 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
  9. ^ a b c d Cite error: The named reference Zorec2016 was invoked but never defined (see the help page).
  10. ^ a b c Cite error: The named reference Zorec2005 was invoked but never defined (see the help page).
  11. ^ a b c d Cite error: The named reference starhorse2 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference vsx was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference balona2019 was invoked but never defined (see the help page).
  16. ^ Eta Piscis Austrini (HIP 108661)[permanent dead link]