Lambda Pegasi

Lambda Pegasi
Diagram showing star positions and boundaries of the Pegasus constellation and its surroundings


Location of λ Pegasi (circled)

Observation data
Epoch J2000      Equinox J2000
Constellation Pegasus
Right ascension 22h 46m 31.87786s[1]
Declination +23° 33′ 56.3561″[1]
Apparent magnitude (V) 3.96[1]
Characteristics
Spectral type G8II-III[2][3]
U−B color index +0.96[1]
B−V color index +1.07[1]
Astrometry
Radial velocity (Rv)-3.9[1] km/s
Proper motion (μ) RA: 55.75[1] mas/yr
Dec.: -10.15[1] mas/yr
Parallax (π)8.93 ± 0.24[4] mas
Distance365 ± 10 ly
(112 ± 3 pc)
Absolute magnitude (MV)-1.45[3]
Details
Mass~1,5[2] M☉
Radius28.5[2][5] R☉
Luminosity390[2] L☉
Temperature4,933[6] K
Metallicity [Fe/H]0.12[6] dex
Rotational velocity (v sin i)8.0[7] km/s
Other designations
Sadalpheretz, Sad Al Faris, λ Peg, 47 Peg, HR 8667, BD +22° 4709, HD 215665, FK5 859, HIP 112440, SAO 90775, GC 31776, IRAS 22441+2318, 2MASS J22463188+2333564
Database references
SIMBADdata

Coordinates: 22h 46m 31.9s, +23° 33′ 56.0″

Lambda Pegasi (λ Peg, λ Pegasi) is a fourth-magnitude star in the constellation Pegasus. It has the traditional name Sadalpheretz,[8] sometimes spelled Sadalpheris or Sad Al Faris, from the Arabic سعد الفرس meaning "Luck of the Stallion", its etymology similar to that of the star Alpheratz, with both referring to the mythological winged-horse Pegasus.

Sadalpheretz is a yellow giant with stellar classification G8II-III. With a mass of 1.5 M☉ and radius that is 28.5 R☉, the star boasts a bolometric luminosity that is roughly 390 L☉.[2] Its apparent magnitude was calibrated in 1983 at 3.96, yielding an intrinsic brightness of -1.45.[3] Parallax calculations place the star at a distance of roughly 112 parsecs from Earth, or 365 ± 10 light years away,[4] about three times the distance of its line-of-sight double Sadalbari.

In the constellation, Lambda and Mu lie to the southwest of Beta Pegasi, the nearest bright star.

See also

References

  1. 1 2 3 4 5 6 7 8 "SIMBAD query result: lam Peg -- Star". Centre de Données astronomiques de Strasbourg. Retrieved 2012-08-28.
  2. 1 2 3 4 5 Smith, G. (November 1998). "Stellar atmospheric parameters for the giant stars MU Pegasi and lambda Pegasi" (PDF). Astronomy & Astrophysics. 339: 531–536. Bibcode:1998A&A...339..531S. Retrieved 2012-08-28.
  3. 1 2 3 "λ Pegasi". Wolfram Alpha. Retrieved 2012-08-28.
  4. 1 2 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  5. ↑ Kaler, James B. "SADALBARI (Lambda and Mu Pegasi)". Stars. University of Illinois. Retrieved 2012-08-28.
  6. 1 2 Koleva, M.; Vazdekis, A. (February 2012). "Stellar population models in the UV. I. Characterisation of the New Generation Stellar Library". Astronomy & Astrophysics. 538, id.A143: A143. arXiv:1111.5449Freely accessible. Bibcode:2012A&A...538A.143K. doi:10.1051/0004-6361/201118065.
  7. ↑ Hekker, S.; Meléndez, J. (December 2007). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics. 475 (3): 1003–1009. arXiv:0709.1145Freely accessible. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233.
  8. ↑ "YILDIZ ADLARI SÖZLÜĞÜ (Glossary of Star Names)". Mustafa Pultar. Retrieved 2012-08-28.
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