Pi Aurigae

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

Pi Aurigae, Latinized from π Aurigae, is the Bayer designation for a single,[11] red-hued star in the northern constellation of Auriga. Located about one degree north of the 2nd magnitude star Beta Aurigae,[12] Pi Aurigae is visible to the naked eye with an apparent visual magnitude of 4.25[2] Based upon parallax measurements, it is approximately 720 light-years (220 parsecs) away from Earth.[1] At that distance, the brightness of the star is diminished by 0.54 in magnitude from extinction caused by interstellar gas and dust.[6]

Pi Aurigae is an evolved bright giant star with a stellar classification of M3 II.[4] After exhausting the supply of hydrogen at its core the star has expanded to approximately 219 times the size of the Sun.[8] It is classified as a slow irregular variable of type LC and its brightness varies from magnitude +4.24 to +4.34.[5] 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.[8]

  1. ^ a b c d e Cite error: The named reference DR3 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Eggen1992 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference araa11_29 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference al32_9_604 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference aaa430_165 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 d e Cite error: The named reference tycho-gaia was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Wu2011 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference omeara2007 was invoked but never defined (see the help page).