Phi Aurigae

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φ Aurigae
Location of φ Aurigae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga[1]
Right ascension 05h 27m 38.884s[2]
Declination +34° 28′ 33.17″[2]
Apparent magnitude (V) 5.089[3]
Characteristics
Spectral type K3 IIIp[4]
U−B color index +1.649[3]
B−V color index +1.411[3]
R−I color index 0.47[citation needed]
Astrometry
Radial velocity (Rv)+30.78±0.21[5] km/s
Proper motion (μ) RA: −1.050 mas/yr[2]
Dec.: −38.934 mas/yr[2]
Parallax (π)6.4359±0.1095 mas[2]
Distance507 ± 9 ly
(155 ± 3 pc)
Absolute magnitude (MV)−0.62[1]
Details
Radius33.97±1.05[6] R☉
Luminosity307±15[6] L☉
Surface gravity (log g)1.75[4] cgs
Temperature4,222[6] K
Metallicity [Fe/H]−0.03[4] dex
Rotational velocity (v sin i)1.6[7] km/s
Other designations
φ Aur, 24 Aurigae, BD+34 1048, HD 35620, HIP 25541, HR 1805, SAO 58051[8]
Database references
SIMBADdata
φ Aurigae in optical light

Phi Aurigae is a giant star in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from φ Aurigae, and abbreviated Phi Aur or φ Aur. This star is faintly visible to the naked eye with an apparent visual magnitude of 5.089.[3] It lies 10′ from another faint naked-eye star HD 35520, between the three open clusters M36 and M38, and NGC 1893.

The distance to this star, as determined from parallax measurements, is approximately 507 light-years (155 parsecs) with a 9 light-year margin of error.[2] It is drifting further away from the Sun with a radial velocity of +31 km/s.[5]

This is an evolved giant star with a stellar classification of K3 IIIp.[4] Having exhausted the supply of hydrogen at its core, it has expanded to 34 times the radius of the Sun. It is radiating over 300[6] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,222 K,[6] giving it the cool orange-hued glow of a K-type star.

References

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  1. ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
  2. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. ^ a b c d Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants.", Monthly Notices of the Royal Astronomical Society, 172 (3): 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
  4. ^ a b c d Cenarro, A. J.; et al. (January 2007), "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters", Monthly Notices of the Royal Astronomical Society, 374 (2): 664–690, arXiv:astro-ph/0611618, Bibcode:2007MNRAS.374..664C, doi:10.1111/j.1365-2966.2006.11196.x, S2CID 119428437.
  5. ^ a b 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, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304.
  6. ^ a b c d e van Belle, Gerard T.; et al. (December 2021), "Direct Measurements of Giant Star Effective Temperatures and Linear Radii: Calibration against Spectral Types and V - K Color", The Astrophysical Journal, 922 (2): 163, arXiv:2107.09205, Bibcode:2021ApJ...922..163V, doi:10.3847/1538-4357/ac1687, ISSN 0004-637X. Phi Aurigae's database entry at VizieR.
  7. ^ De Medeiros, J. R.; et al. (November 2000), "Rotation and lithium in single giant stars", Astronomy and Astrophysics, 363: 239–243, arXiv:astro-ph/0010273, Bibcode:2000A&A...363..239D.
  8. ^ "phi Aur". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-08-23.
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