Astronomy:Pi Aurigae

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Short description: Star in the constellation Auriga
Pi Aurigae
The location of π Aurigae (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Auriga[1]
Right ascension  05h 59m 56.09792s[2]
Declination +45° 56′ 12.2457″[2]
Apparent magnitude (V) 4.25[3]
Characteristics
Evolutionary stage asymptotic giant branch[4]
Spectral type M3 IIb[5]
U−B color index +1.83[3]
B−V color index +1.72[3]
Variable type LC[6]
Astrometry
Radial velocity (Rv)0.71±0.76[7] km/s
Proper motion (μ) RA: −3.755[2] mas/yr
Dec.: −7.785[2] mas/yr
Parallax (π)4.515 ± 0.241[2] mas
Distance720 ± 40 ly
(220 ± 10 pc)
Absolute magnitude (MV)−2.46[1]
Details
Mass2.98[8] M☉
Radius218.6[9] R☉
Luminosity6,630±1,054[9] L☉
Surface gravity (log g)0.55±0.10[10] cgs
Temperature3,525±125[9] K
Metallicity [Fe/H]0.03±0.04[10] dex
Other designations
π Aur, 35 Aurigae, BD+45 1217, HD 40239, HIP 28404, HR 2091, SAO 40756[11]
Database references
SIMBADdata
π Aurigae (center) in optical light

Pi Aurigae is a single,[12] red-hued star in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from π Aurigae, and abbreviated Pi Aur or π Aur. Located about one degree north of the 2nd magnitude star Beta Aurigae,[13] Pi Aurigae is visible to the naked eye with an apparent visual magnitude of 4.25[3] Based upon parallax measurements, it is approximately 720 light-years (220 parsecs) away from Earth.[2] At that distance, the brightness of the star is diminished by 0.54 in magnitude from extinction caused by interstellar gas and dust.[7]

Pi Aurigae is an evolved bright giant star with a stellar classification of M3 IIb.[5] After exhausting the supply of hydrogen at its core the star has expanded to approximately 219 times the size of the Sun.[9] It is classified as a slow irregular variable of type LC and its brightness varies from magnitude +4.24 to +4.34.[6] On average, the star is radiating 6,630 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,525 K.[9]

References

  1. ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.  XHIP record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940.  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J. 
  4. ↑ Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal 104 (1): 275–313, doi:10.1086/116239, Bibcode: 1992AJ....104..275E. 
  5. ↑ 5.0 5.1 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, Bibcode: 1989ApJS...71..245K. 
  6. ↑ 6.0 6.1 Ruban, E. V. et al. (September 2006), "Spectrophotometric observations of variable stars", Astronomy Letters 32 (9): 604–607, doi:10.1134/S1063773706090052, Bibcode: 2006AstL...32..604R. 
  7. ↑ 7.0 7.1 Famaey, B. et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics 430 (1): 165–186, doi:10.1051/0004-6361:20041272, Bibcode: 2005A&A...430..165F. 
  8. ↑ Khalatyan, A.; Anders, F.; Chiappini, C.; Queiroz, A. B. A.; Nepal, S.; Dal Ponte, M.; Jordi, C.; Guiglion, G. et al. (2024). "Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost". Astronomy and Astrophysics 691: A98. doi:10.1051/0004-6361/202451427. Bibcode: 2024A&A...691A..98K. 
  9. ↑ 9.0 9.1 9.2 9.3 9.4 McDonald, I. et al. (October 2017), "Fundamental parameters and infrared excesses of Tycho-Gaia stars", Monthly Notices of the Royal Astronomical Society 471 (1): 770–791, doi:10.1093/mnras/stx1433, ISSN 0035-8711, Bibcode: 2017MNRAS.471..770M  Pi Aurigae's database entry at VizieR.
  10. ↑ 10.0 10.1 Wu, Yue et al. (January 2011), "Coudé-feed stellar spectral library - atmospheric parameters", Astronomy and Astrophysics 525: A71, doi:10.1051/0004-6361/201015014, Bibcode: 2011A&A...525A..71W. 
  11. ↑ "pi. Aur". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=pi.+Aur. 
  12. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E. 
  13. ↑ O'Meara, Stephen James (2007), Steve O'Meara's Herschel 400 Observing Guide, Cambridge University Press, p. 23, ISBN 978-0521858939, https://books.google.com/books?id=Nyh9fAC_tpIC&pg=PA23.