33 Pegasi

From Wikipedia, the free encyclopedia
Jump to: navigation, search
33 Pegasi
Observation data
Epoch J2000      Equinox J2000
Constellation Pegasus
Right ascension 22h 23m 39.56438s[1]
Declination 20° 50′ 53.6239″[1]
Apparent magnitude (V) 6.203[2] (6.391/9.287)[3]
Spectral type F7 V[4]
Radial velocity (Rv) 23.8 ± 0.4[2] km/s
Proper motion (μ) RA: +334.55[1] mas/yr
Dec.: –14.86[1] mas/yr
Parallax (π) 29.67 ± 0.65[1] mas
Distance 110 ± 2 ly
(33.7 ± 0.7 pc)
Absolute magnitude (MV) 3.55[2]
33 Peg A
Surface gravity (log g) 4.29[5] cgs
Temperature 6,169[6] K
Metallicity [Fe/H] –0.18[6] dex
Rotational velocity (v sin i) 6[2] km/s
Age 4.1[6] Gyr
Other designations
33 Peg, BD–16 4196, HD 212395, HIP 110548, HR 8532, SAO 90462.[7]

33 Pegasi is the Flamsteed designation for a visual binary star in the northern constellation of Pegasus. It has an apparent visual magnitude of 6.2,[2] placing it near the limit of naked eye visibility. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.02967″,[1] which is equivalent to a distance of roughly 110 ly (34 pc) from the Sun.

The primary component of this system is a main sequence star with a visual magnitude of 6.4[3] and a stellar classification of F7 V.[4] It is nearly as old as the Sun with an estimated age of 4.1 billion years, but has a lower abundance of elements other than hydrogen and helium. The stellar atmosphere has an effective temperature of 6,169 K,[6] giving it the yellow-white glow of an F-type star.[8]

A faint, magnitude 9.3 companion star is located at an angular separation of 0.420 arc seconds along a position angle of 0.0°.[3] The orbital period of this pair is large enough that it has not be computed based on current observations.[9]


  1. ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d e Nordström, B. et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs", Astronomy and Astrophysics 418: 989–1019, arXiv:astro-ph/0405198, Bibcode:2004A&A...418..989N, doi:10.1051/0004-6361:20035959. 
  3. ^ a b c Fabricius, C.; Makarov, V. V. (April 2000), "Two-colour photometry for 9473 components of close Hipparcos double and multiple stars", Astronomy and Astrophysics 356: 141–145, Bibcode:2000A&A...356..141F. 
  4. ^ a b Harlan, E. A.; Taylor, D. C. (March 1970), "MK classification for F- and G-type stars. II", Astronomical Journal 75 (2): 165–166, Bibcode:1970AJ.....75..165H, doi:10.1086/110956. 
  5. ^ Boesgaard, Ann Merchant et al. (June 2011), "The Correlation of Lithium and Beryllium in F and G Field and Cluster Dwarf Stars", The Astrophysical Journal 530: A138, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276. 
  6. ^ a b c d Casagrande, L. et al. (June 2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy & Astrophysics 530: A138, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276. 
  7. ^ "33 Peg -- Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), retrieved 2013-12-31. 
  8. ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16. 
  9. ^ Söderhjelm, Staffan (January 1999), "Visual binary orbits and masses post Hipparcos", Astronomy and Astrophysics 341: 121–140, Bibcode:1999A&A...341..121S. 

Coordinates: Sky map 22h 23m 39.564s, +20° 50′ 53.62″