Astronomy:Psi2 Aquarii

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Short description: Star in the constellation Aquarius
ψ2 Aquarii
Aquarius constellation map.svg
Red circle.svg
Location of ψ2 Aquarii (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Aquarius
Right ascension  23h 17m 54.21372s[1]
Declination −09° 10′ 57.0675″[1]
Apparent magnitude (V) 4.403[2]
Characteristics
Spectral type B5 Vn[3]
U−B color index −0.561[2]
B−V color index −0.146[2]
Variable type λ Eri[4]
Astrometry
Radial velocity (Rv)−6[5] km/s
Proper motion (μ) RA: +17.13[1] mas/yr
Dec.: −11.70[1] mas/yr
Parallax (π)8.12 ± 0.38[1] mas
Distance400 ± 20 ly
(123 ± 6 pc)
Absolute magnitude (MV)−1.04[6]
Details
Radius4.6[7] R
Luminosity565[6] L
Temperature15,212 ± 288[7] K
Rotational velocity (v sin i)341[8] km/s
Other designations
ψ2 Aqr, 93 Aquarii, BD−09°6160, HD 219688, HIP 115033, HR 8858, SAO 146620.[9]
Database references
SIMBADdata

Psi2 Aquarii, Latinized from ψ2 Aquarii, is the Bayer designation for a star in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of 4.4.[2] Based upon parallax measurements made during the Hipparcos mission, the distance to this star is roughly 400 light-years (120 parsecs).[1]

A light curve for Psi2 Aquarii, plotted from TESS data[10]

This is a B-type main sequence star with a stellar classification of B5 Vn.[3] The 'n' suffix indicates that the absorption lines in the spectrum are being broadened by Doppler shift from the star's rapid rotation rate. The projected rotational velocity of the star is 341 km/s.[8] Psi2 Aquarii is 4.6[7] times as large as the Sun with an effective temperature of 15,212 K[7] in its outer envelope.

It is a λ Eridani variable, or periodic Be star, with a pulsation cycle lasting 1.073 days.[4] The amplitude of the variation is 0.024 in magnitude.[11]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 2.3 Kozok, J. R. (September 1985), "Photometric observations of emission B-stars in the southern Milky Way", Astronomy and Astrophysics Supplement Series 61: 387–405, Bibcode1985A&AS...61..387K. 
  3. 3.0 3.1 Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement 17: 371, doi:10.1086/190179, Bibcode1968ApJS...17..371L. 
  4. 4.0 4.1 Balona, L. A. (December 1995), "Tests of the Pulsation and Starspot Models for the Periodic Be-Stars", Monthly Notices of the Royal Astronomical Society 277 (4): 1547, doi:10.1093/mnras/277.4.1547, Bibcode1995MNRAS.277.1547B. 
  5. Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication (Washington: Carnegie Institution of Washington), Bibcode1953GCRV..C......0W. 
  6. 6.0 6.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  7. 7.0 7.1 7.2 7.3 Underhill, A. B. et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society 189 (3): 601–605, doi:10.1093/mnras/189.3.601, Bibcode1979MNRAS.189..601U. 
  8. 8.0 8.1 Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago 239 (1): 1, Bibcode1970CoAsi.239....1B. 
  9. "* 93 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+93+Aqr. 
  10. MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html, retrieved 10 November 2022. 
  11. Balona, L. A. (July 1990), "Short-period variability in Be stars", Monthly Notices of the Royal Astronomical Society 245: 92–100, doi:10.1093/mnras/245.1.92, Bibcode1990MNRAS.245...92B. 

External links