55 Pegasi

55 Pegasi
Location of 55 Pegasi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Pegasus
Right ascension 23h 07m 00.25899s[1]
Declination 9° 24′ 34.1741″[1]
Apparent magnitude (V) 4.51[2]
Characteristics
Evolutionary stage AGB
Spectral type M1IIIab[3]
U−B color index +1.88[2]
B−V color index +1.58[2]
Variable type suspected[4]
Astrometry
Radial velocity (Rv)−5.34[5] km/s
Proper motion (μ) RA: +6.41[6] mas/yr
Dec.: –12.71[6] mas/yr
Parallax (π)10.7831 ± 0.2694 mas[1]
Distance302 ± 8 ly
(93 ± 2 pc)
Absolute magnitude (MV)–0.48[7]
Details[8]
Mass1.61±0.13 M☉
Radius45.87+1.31
−1.38 R☉
Luminosity483.1±37.2 L☉
Surface gravity (log g)0.80 cgs
Temperature3,994±50 K
Metallicity [Fe/H]0.23 dex
Rotational velocity (v sin i)3.8±1.5[9] km/s
Age2.13±0.46 Gyr
Other designations
55 Peg, NSV 14428, BD+08°4997, FK5 1603, GC 32196, HD 218329, HIP 114144, HR 8795, SAO 127976[10]
Database references
SIMBADdata

55 Pegasi is a single[11] star in the northern constellation of Pegasus. It is visible to the naked eye as a faint, reddish-hued point of light with a baseline apparent visual magnitude of 4.51.[2] The star is located approximately 302 light years away from the Sun based on parallax,[1] but it is moving closer with a radial velocity of −5 km/s.[5]

This is an aging red giant star on the asymptotic giant branch[12] with a stellar classification of M1IIIab,[3] having exhausted the supply of hydrogen at its core then expanded to 46 times the Sun's radius. It is a suspected variable, with an observed magnitude that ranges from 4.50 down to 4.56.[4] The star is around two billion years old with 1.6 times the mass of the Sun. It is radiating 483 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,994 K.[8]

  1. ^ a b c d Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Ducati2002 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Keenan1989 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference AAVSO was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Famaey2005 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference XHIP was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Baines2018 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Zamanov2008 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 Eggen1992 was invoked but never defined (see the help page).