Astronomy:Psi Pegasi

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Short description: Binary star system in the constellation Pegasus
Psi Pegasi
Pegasus constellation map.svg
Red circle.svg
Location of ψ Pegasi (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Pegasus
Right ascension  23h 57m 45.52681s[1]
Declination 25° 08′ 29.0480″[1]
Apparent magnitude (V) 4.66[2]
Characteristics
Spectral type M3III[3]
U−B color index +1.66[2]
B−V color index +1.59[2]
Variable type suspected[4]
Astrometry
Radial velocity (Rv)−6.59±0.23[5] km/s
Proper motion (μ) RA: −35.24[1] mas/yr
Dec.: −31.60[1] mas/yr
Parallax (π)6.85 ± 0.24[1] mas
Distance480 ± 20 ly
(146 ± 5 pc)
Absolute magnitude (MV)–1.19[6]
Orbit[7]
Period (P)55.06±11.31 yr
Semi-major axis (a)0.170±0.016
Eccentricity (e)0.19±0.10
Inclination (i)65.6±2.2°
Longitude of the node (Ω)46.6±2.3°
Periastron epoch (T)2,001.83±8.81
Argument of periastron (ω)
(secondary)
159.7±11.9°
Details
Radius98±6[8] R
Luminosity960[6] L
Temperature3,882[9] K
Other designations
ψ Peg, 84 Pegasi, NSV 14777, BD+24°4865, FK5 1629, GC 33230, HD 224427, HIP 118131, HR 9064, SAO 91611, WDS J23578+2508AB[10]
Database references
SIMBADdata

Psi Pegasi, which is Latinized from ψ Pegasi, is a binary star system within the great square[11] in the northern constellation of Pegasus. It has a red hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.66.[2] This object is located at a distance of approximately 476 light-years away from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −6.6 km/s.[5]

A visual band light curve for Psi Pegasi, plotted from data published by Tabur et al. (2009)[12]

The orbital elements for this system were computed for the first time in 2004 based on interferometric observations, yielding an orbital period of roughly 55 years and an eccentricity of about 0.19.[7][13][14] The visible component is an aging red giant star on the asymptotic giant branch[15] with a stellar classification of M3III.[3] It is a suspected variable, probably semiregular, with its magnitude varying from 4.63 to 4.69[4][16] over periods of 37.4 and 118.9 days.[12] With the supply of hydrogen exhausted at its core, the star has cooled and expanded to around 98[8] times the Sun's radius. It is radiating 960[6] times the luminosity of the Sun from its bloated photosphere at an effective temperature of 3,882 K.[9]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode2007A&A...474..653V.  Vizier catalog entry
  2. 2.0 2.1 2.2 2.3 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues 2237. Bibcode2002yCat.2237....0D. 
  3. 3.0 3.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode1989ApJS...71..245K. 
  4. 4.0 4.1 Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1. Bibcode2009yCat....102025S. 
  5. 5.0 5.1 Famaey, B. et al. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data". Astronomy & Astrophysics 430: 165–186. doi:10.1051/0004-6361:20041272. Bibcode2005A&A...430..165F. 
  6. 6.0 6.1 6.2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode2012AstL...38..331A.  Vizier catalog entry
  7. 7.0 7.1 Olevic, D.; Cvetkovic, Z. (2004). "Orbits of 6 Binaries". Serbian Astronomical Journal 168 (168): 25. doi:10.2298/SAJ0468025O. Bibcode2004SerAJ.168...25O. 
  8. 8.0 8.1 Arroyo-Torres, B. et al. (June 2014), "VLTI/AMBER observations of cold giant stars: atmospheric structures and fundamental parameters", Astronomy & Astrophysics 566: 11, doi:10.1051/0004-6361/201323264, A88, Bibcode2014A&A...566A..88A. 
  9. 9.0 9.1 Martínez, M. Isabel Pérez et al. (2011). "The basal chromospheric Mg ii h+k flux of evolved stars: Probing the energy dissipation of giant chromospheres". Monthly Notices of the Royal Astronomical Society 414 (1): 418. doi:10.1111/j.1365-2966.2011.18421.x. Bibcode2011MNRAS.414..418P.  Vizier catalog entry
  10. "psi Peg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=psi+Peg. 
  11. Harrington, Philip S. (2010). Cosmic Challenge: The Ultimate Observing List for Amateurs. Cambridge University Press. p. 50. ISBN 9781139493680. https://books.google.com/books?id=8mQmvT4wpWQC&pg=PA50. 
  12. 12.0 12.1 Tabur, V.; Bedding, T. R.; Kiss, L. L.; Moon, T. T.; Szeidl, B.; Kjeldsen, H. (December 2009). "Long-term photometry and periods for 261 nearby pulsating M giants". Monthly Notices of the Royal Astronomical Society 400 (4): 1945–1961. doi:10.1111/j.1365-2966.2009.15588.x. Bibcode2009MNRAS.400.1945T. 
  13. Malkov, O. Yu.; Tamazian, V. S.; Docobo, J. A.; Chulkov, D. A. (2012). "Dynamical masses of a selected sample of orbital binaries". Astronomy & Astrophysics 546: A69. doi:10.1051/0004-6361/201219774. Bibcode2012A&A...546A..69M.  Vizier catalog entry
  14. Mason, Brian D. et al. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal 122 (6): 3466. doi:10.1086/323920. Bibcode2001AJ....122.3466M.  Vizier catalog entry
  15. Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal 104 (1): 275–313, doi:10.1086/116239, Bibcode1992AJ....104..275E. 
  16. Watson, C. L. (2006). "The International Variable Star Index (VSX)". The Society for Astronomical Sciences 25th Annual Symposium on Telescope Science. Held May 23–25 25: 47. Bibcode2006SASS...25...47W.