Xi2 Sagittarii, Latinized from ξ2 Sagittarii, is a star in the zodiac constellation of Sagittarius. Data collected during the Hipparcos mission suggests it is an astrometric binary, although nothing is known about the companion.[8][9] It is visible to the naked eye with a combined apparent visual magnitude of +3.51.[2] Based upon an annual parallax shift of 8.4 mas as seen from Earth,[1] this system is located around 390 light years from the Sun.

Xi2 Sagittarii
Location of ξ2 Sagittarii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 18h 57m 43.80s[1]
Declination −21° 06′ 23.97″[1]
Apparent magnitude (V) +3.51[2]
Characteristics
Spectral type G8/K0 II/III[3]
U−B color index +1.13[2]
B−V color index +1.18[2]
Astrometry
Radial velocity (Rv)−20.10[4] km/s
Proper motion (μ) RA: 33.52 mas/yr[1]
Dec.: -13.552 mas/yr[1]
Parallax (π)8.4092 ± 0.1972 mas[1]
Distance388 ± 9 ly
(119 ± 3 pc)[1]
Absolute magnitude (MV)−1.72[5]
Details[6]
Mass3.627±0.143 M
Radius26.747±1.97 R
Luminosity676[4] L
Surface gravity (log g)2.39±0.19 cgs
Temperature4,682±75 K
Metallicity [Fe/H]0±0.5 dex
Age253±33 Myr
Other designations
ξ2 Sgr, 37 Sgr, BD−21° 5201, FK5 710, HD 175775, HIP 93085, HR 7150, SAO 187504[7]
Database references
SIMBADdata

The spectrum of Xi2 Sagittarii yields a mixed stellar classification of G8/K0 II/III,[3] showing traits of a G- or K-type giant or bright giant star. It has an estimated 3.6. times the mass of the Sun and about 27 times the Sun's radius. [6] At an age of around 380 million years, it is radiating 676 times the Sun's luminosity from its photosphere at an effective temperature of 4,541 K.[4]

References

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  1. ^ a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  3. ^ a b Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
  4. ^ a b c Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal, 150 (3), 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  6. ^ a b Gomes da Silva, J.; Santos, N. C.; Adibekyan, V.; Sousa, S. G.; Campante, T. L.; Figueira, P.; Bossini, D.; Delgado-Mena, E.; Monteiro, M. J. P. F. G.; de Laverny, P.; Recio-Blanco, A.; Lovis, C. (2021-02-01). "Stellar chromospheric activity of 1674 FGK stars from the AMBRE-HARPS sample. I. A catalogue of homogeneous chromospheric activity". Astronomy and Astrophysics. 646: A77. arXiv:2012.10199. doi:10.1051/0004-6361/202039765. ISSN 0004-6361. Xi2 Sagittarii's database entry at VizieR.
  7. ^ "ksi02 Sgr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-05.
  8. ^ Frankowski, A.; et al. (March 2007), "Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data", Astronomy and Astrophysics, 464 (1): 377–392, arXiv:astro-ph/0612449, Bibcode:2007A&A...464..377F, doi:10.1051/0004-6361:20065526, S2CID 14010423.
  9. ^ Makarov, V. V.; Kaplan, G. H. (May 2005), "Statistical Constraints for Astrometric Binaries with Nonlinear Motion", The Astronomical Journal, 129 (5): 2420–2427, Bibcode:2005AJ....129.2420M, doi:10.1086/429590.