Sigma Pegasi

Sigma Pegasi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Pegasus
Right ascension 22h 52m 24.07496s[1]
Declination +09° 50′ 08.3791″[1]
Apparent magnitude (V) 5.16[2] + 13.5[3]
Characteristics
Spectral type F6 V[4] or F7 IV[5] + M4 V[3]
U−B color index −0.016[2]
B−V color index +0.486[2]
Astrometry
Radial velocity (Rv)+11.4[6] km/s
Proper motion (μ) RA: +521.04[1] mas/yr
Dec.: +42.65[1] mas/yr
Parallax (π)36.66 ± 0.29 mas[1]
Distance89.0 ± 0.7 ly
(27.3 ± 0.2 pc)
Absolute magnitude (MV)3.01[7]
Details
σ Peg A
Mass1.275[6] M☉
Surface gravity (log g)3.69[4] cgs
Temperature6,250[4] K
Metallicity [Fe/H]−0.32[4] dex
Rotational velocity (v sin i)3[8] km/s
Age2.71±0.61[9] Gyr
Other designations
σ Peg, 49 Peg, BD+09° 5122, FK5 3828, HD 216385, HIP 112935, HR 8697, SAO 127810[10]
Database references
SIMBADdata

σ Pegasi, Latinised as Sigma Pegasi, is a binary star[3] system in the northern constellation of Pegasus. With a combined apparent visual magnitude of 5.16,[2] it is faintly visible to the naked eye. Based upon an annual parallax shift of 36.66 mas as seen from Earth,[1] the system is located 89 light years distant from the Sun. It has a relatively high proper motion, advancing across the celestial sphere at the rate of 0.524 arcseconds per year.[11]

The primary, component A, is a yellow-white hued F-type main-sequence star with a stellar classification of F6 V.[4] However, Frasca et al. (2009) lists it as a somewhat more evolved F-type subgiant star with a class of F7 IV.[5] At the age of 2.7[9] billion years, it has an inactive chromosphere[4] and is spinning with a leisurely projected rotational velocity of 3 km/s.[8] It has a faint, magnitude 13.23[12] red dwarf companion, designated component B, at an angular separation of 248 arc seconds.[3] The system is most likely (96% chance) a member of the thin disk population of the Milky Way.[6]

  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 Nicolet1978 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  4. ^ a b c d e f Cite error: The named reference Gray2006 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Frasca2009 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Ramirez2013 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Karatas2006 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Takeda2005 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Pace2013 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 Lepine2005 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Lepine2007 was invoked but never defined (see the help page).