34 Pegasi

34 Pegasi
Observation data
Epoch J2000      Equinox J2000
Constellation Pegasus
Right ascension 22h 26m 37.37059s[1]
Declination +04° 23′ 37.6056″[1]
Apparent magnitude (V) 5.76[2]
Characteristics
Spectral type F7V[3] or F8IV−V[4] + K4[5]
B−V color index 0.519±0.005[2]
Astrometry
Radial velocity (Rv)−13.5±0.2[2] km/s
Proper motion (μ) RA: +307.781[1] mas/yr
Dec.: +47.533[1] mas/yr
Parallax (π)24.9028 ± 0.1794 mas[1]
Distance131.0 ± 0.9 ly
(40.2 ± 0.3 pc)
Absolute magnitude (MV)2.85[4]
Orbit[4]
PrimaryAa
CompanionAb
Period (P)929.91±0.46 d
Semi-major axis (a)9.5±0.3"
(≥58.24±0.65 Gm)
Eccentricity (e)0.4358±0.0062
Inclination (i)94.0±5.1°
Longitude of the node (Ω)101.6±4.6°
Periastron epoch (T)53,293.9±3.2 HJD
Argument of periastron (ω)
(secondary)
188.5±1.1°
Semi-amplitude (K1)
(primary)
5.060±0.054 km/s
Details
Aa
Mass1.33[6] M
Radius2.25+0.07
−0.08
[1] R
Luminosity6.7±0.1[1] L
Surface gravity (log g)3.92[6] cgs
Temperature6,200+110
−100
[1] K
Metallicity [Fe/H]−0.04±0.02[2] dex
Rotational velocity (v sin i)8.4±1.0[4] km/s
Age3.22[6] Gyr
Ab
Mass0.29[4] M
Other designations
BU 290[7], BD+03°4705, GJ 9782, HD 212754, HIP 110785, HR 8548, SAO 127529, WDS J22266+0424, BU 290[8]
Database references
SIMBADdata

34 Pegasi is a triple star[7] system in the northern constellation of Pegasus. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.76.[2] The system is located at a distance of 131 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −13.5 km/s.[2] It has been catalogued as a member of the Hyades Supercluster,[9] although its membership status remains doubtful.

The innermost system is a single-lined spectroscopic binary with an orbital period of 2.55 years and an eccentricity of 0.44.[4] The orbital plane of this pair is being viewed nearly edge-on, and has an angular semimajor axis of 9.5.[4] A third member of the system has a poorly-constrained 420 year orbit around the main pair.[10] This star was discovered by Burnham in 1874,[5] and the discovery code BU 290 was given to the double. As of 2015, it lies at an angular separation of 3.90±0.02 along a position angle of 226.2°±0.8° from the inner system.[7]

The primary member, component Aa, is an F-type main-sequence star that is starting to evolve off the main sequence,[4] with stellar classifications of F7V[3] or F8IV−V,[4] depending on the source. It is around three[6] billion years old and is spinning with a projected rotational velocity of 8 km/s,[4] with a measured rotation period of 12 days.[5] The star has 1.3[6] times the mass of the Sun and 2.25[1] times the Sun's radius. It is radiating 6.7[1] times the luminosity of the Sun from its photosphere at an effective temperature of 6,200 K.[1]

The secondary companion to the primary, component Ab, is most likely a red dwarf[5] star with around 29% of the mass of the Sun.[4] The tertiary member, component B, has 53%[11] of the Sun's mass and a class of around K4.[5]

  1. ^ a b c d e f g h i j k Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Houk1999 was invoked but never defined (see the help page).
  4. ^ a b c d e f g h i j k Cite error: The named reference Willmarth2016 was invoked but never defined (see the help page).
  5. ^ a b c d e Cite error: The named reference Griffin2010 was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference Earle2017 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Roberts2017 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggen1992 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Tokovinin2016 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference tokovinin2014 was invoked but never defined (see the help page).