Chi Pegasi

Chi Pegasi
Location of χ Pegasi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Pegasus
Right ascension 00h 14m 36.16451s[1]
Declination 20° 12′ 24.1205″[1]
Apparent magnitude (V) 4.80[2]
Characteristics
Evolutionary stage asymptotic giant branch[3]
Spectral type M2+III[4]
U−B color index +1.91[2]
B−V color index +1.57[2]
Variable type suspected[5]
Astrometry
Radial velocity (Rv)−46.26±0.57[6] km/s
Proper motion (μ) RA: +90.76[1] mas/yr
Dec.: +1.24[1] mas/yr
Parallax (π)8.86 ± 0.22 mas[1]
Distance368 ± 9 ly
(113 ± 3 pc)
Absolute magnitude (MV)−0.47[7]
Details[8]
Mass1.06±0.11 M☉
Radius52.88+1.31
−1.37 R☉
Luminosity435±23[9] L☉
Surface gravity (log g)0.80 cgs
Temperature3,842±49 K
Metallicity [Fe/H]0.00 dex
Rotational velocity (v sin i)6.0[6] km/s
Age7.70±2.01 Gyr
Other designations
χ Peg, 89 Pegasi, NSV 99, BD+19°27, FK5 1004, GC 270, HD 1013, HIP 1168, HR 45, SAO 91792[10]
Database references
SIMBADdata

Chi Pegasi, Latinised from χ Pegasi, is a single[11] star in the northern constellation of Pegasus, along the eastern constellation border with Pisces. It has a reddish hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.80.[2] The distance to this star is approximately 368 light-years based on parallax,[1] but it is drifting closer with a radial velocity of −46 km/s.[6]

A light curve for Chi Pegasi, plotted from Hipparcos data[12]

This is an aging red giant star on the asymptotic giant branch[3] with a stellar classification of M2+III.[4] It is about 8 billion years old with a mass 6% greater than the Sun's. With the supply of hydrogen at its core exhausted, the star has cooled and expanded to 53 times the girth of the Sun. It is radiating around 435 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,842 K.[8]

Chi Pegasi is a suspected small-amplitude variable.[5] Koen and Eyer examined the Hipparcos data for Chi Pegasi, and found that its brightness varied by 0.0094 magnitudes, with a period of 5.9641 days.[13]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 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 Eggen1992 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference perkins1989 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Percy1994 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Massarotti2008 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 GaiaDR2 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 HIPCurve was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Koen was invoked but never defined (see the help page).