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85 Pegasi

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85 Pegasi A/B
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Pegasus
Right ascension 00h 02m 10.16s[1]
Declination +27° 04′ 56.1″[1]
Apparent magnitude (V) 5.75 / 8.89
Characteristics
A
Evolutionary stage subgiant[2]
Spectral type G5IV[2]
B
Spectral type K6-8V[2]
Astrometry
Proper motion (μ) RA: 780.22 ± 2.01[1] mas/yr
Dec.: -917.75 ± 1.20[1] mas/yr
Parallax (π)82.5±0.8 mas[3]
Distance39.5 ± 0.4 ly
(12.1 ± 0.1 pc)
Absolute magnitude (MV)5.32 + 7.68 + 11.19[4]
Orbit
Companion85 Pegasi B
Period (P)26.28 yr
Semi-major axis (a)0.83″
Eccentricity (e)0.38
Inclination (i)49°
Details
A
Mass0.75±0.01[5] M
Radius0.948±0.011[6] R
Luminosity0.712±0.011[6] L
Surface gravity (log g)4.337±0.012[5] cgs
Temperature5,445±30[6] K
Metallicity [Fe/H]−0.81[5] dex
Age9.3±0.5[2] Gyr
9–11[4] Gyr
Ba
Mass0.72±0.05[2] M
Radius0.512[4] R
Luminosity0.074[4] L
Surface gravity (log g)4.8±0.2[2] cgs
Temperature4,200±200[2] K
Bb
Mass0.14[4] M
Radius0.155[4] R
Luminosity0.003[4] L
Surface gravity (log g)5.18[4] cgs
Temperature3,330[4] K
Other designations
BDS 12701, HR 9088, HD 224930, LFT 1848, LHS 101, LTT 17088, SAO 91669, HIP 171.
85 Pegasi A: ADS 17175 A, GJ 914 A, BD +26°4734 A, BU 733 A.
85 Pegasi B: ADS 17175 B, GJ 914 B, BD +26°4734 B, BU 733 B.
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata

85 Pegasi is a multiple star system 39.5 light years away[3] in the constellation of Pegasus. The primary component is sixth magnitude 85 Pegasi A, which is a yellow dwarf like the Sun. The secondary component, 85 Pegasi B, is a ninth magnitude orange dwarf that takes 26.28 years to orbit at 10.3 AU around the primary in an elliptical orbit. The orbital distance ranges from 6.4 AU at periastron to 14.2 AU at apastron. 85 Pegasi B may itself be a binary, with a close, faint red dwarf companion (designated 85 Pegasi Bb) separated by 2 AU from the primary (designated 85 Pegasi Ba). The mass would be 11% solar mass (M). All components in the star system including Star A are smaller, cooler and less massive, luminous, and metallic than the Sun and 51 Pegasi.

An infrared excess has been detected around the primary, most likely indicating the presence of a circumstellar disk at a radius of more than 97 AU. The temperature of this dust is below 25 K.[7]

References

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  1. ^ a b c d 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. S2CID 18759600. Vizier catalog entry
  2. ^ a b c d e f g Huber, D.; Matthews, J. M.; Croll, B.; Obbrugger, M.; Gruberbauer, M.; Guenther, D. B.; Weiss, W. W.; Rowe, J. F.; Kallinger, T.; Kuschnig, R.; Scholtz, A. L.; Moffat, A. F. J.; Rucinski, S. M.; Sasselov, D.; Walker, G. a. H. (2009-10-01). "A search for p-modes and other variability in the binary system 85 Pegasi using MOST photometry". Astronomy & Astrophysics. 505 (2): 715–725. doi:10.1051/0004-6361/200912139. ISSN 0004-6361.
  3. ^ a b Söderhjelm, S. (January 1999). "Visual binary orbits and masses POST HIPPARCOS". Astronomy and Astrophysics. 341: 121–140. Bibcode:1999A&A...341..121S. Vizier catalog entry
  4. ^ a b c d e f g h i Bach, K.; Lee, J.; Demarque, P.; Kim, Y.-C. (2009-09-20). "Evolutionary status of 85 Pegasi". The Astrophysical Journal. 703 (1): 362–369. doi:10.1088/0004-637X/703/1/362. ISSN 0004-637X.
  5. ^ a b c Karovicova, I.; White, T. R.; Nordlander, T.; Casagrande, L.; Ireland, M.; Huber, D.; Jofré, P. (2020-08-01). "Fundamental stellar parameters of benchmark stars from CHARA interferometry - I. Metal-poor stars". Astronomy & Astrophysics. 640: A25. arXiv:2006.05411. Bibcode:2020A&A...640A..25K. doi:10.1051/0004-6361/202037590. ISSN 0004-6361.{{cite journal}}: CS1 maint: postscript (link)
  6. ^ a b c Soubiran, C.; Creevey, O. L.; Lagarde, N.; Brouillet, N.; Jofré, P.; Casamiquela, L.; Heiter, U.; Aguilera-Gómez, C.; Vitali, S.; Worley, C.; de Brito Silva, D. (2024-02-01). "Gaia FGK benchmark stars: Fundamental Teff and log g of the third version". Astronomy and Astrophysics. 682: A145. arXiv:2310.11302. Bibcode:2024A&A...682A.145S. doi:10.1051/0004-6361/202347136. ISSN 0004-6361. 85 Peg's database entry at VizieR.
  7. ^ Eiroa, C.; et al. (July 2013). "DUst around NEarby Stars. The survey observational results". Astronomy & Astrophysics. 555: A11. arXiv:1305.0155. Bibcode:2013A&A...555A..11E. doi:10.1051/0004-6361/201321050. S2CID 377244.
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