Xi1 Sagittarii

Xi1 Sagittarii (ξ1 Sagittarii) is a solitary,[11] blue-white hued star in the zodiac constellation of Sagittarius. It is visible to the naked eye with an apparent visual magnitude of +5.06.[2] Based upon a small annual parallax shift of 1.58 mas as seen from Earth,[1] this system is located roughly 2,100 light years from the Sun.

Xi1 Sagittarii
Location of ξ1 Sagittarii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 18h 57m 20.47670s[1]
Declination −20° 39 22.8539[1]
Apparent magnitude (V) +5.06[2]
Characteristics
Spectral type B9/A0 Ib[3]
U−B color index −0.14[2]
B−V color index +0.12[2]
Astrometry
Proper motion (μ) RA: −1.46[1] mas/yr
Dec.: −5.75[1] mas/yr
Parallax (π)1.58 ± 0.26[1] mas
Distanceapprox. 2,100 ly
(approx. 600 pc)
Absolute magnitude (MV)−3.92[4]
Details
Mass7.8±0.1[5] M
Radius15[6] R
Luminosity2,753[7] L
Surface gravity (log g)2.3[8] cgs
Temperature9,400[8] K
Metallicity [Fe/H]−0.20[8] dex
Rotational velocity (v sin i)10[9] km/s
Age39.8±4.9[5] Myr
Other designations
ξ1 Sgr, 36 Sgr, BD−20° 5339, HD 175687, HIP 93057, HR 7145, SAO 187498[10]
Database references
SIMBADdata

This is a massive supergiant star[6] with a stellar classification of B9/A0 Ib.[3] With an estimated 7.8[5] times the mass of the Sun and an age of about 40[5] million years it has depleted the hydrogen at its core, causing it to expand to about 15 times the Sun's radius.[6] It is radiating 2,753[7] times the Sun's luminosity from its photosphere at an effective temperature of about 9,400 K.[8]

References

  1. van Leeuwen, F. (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. Fernie, J. D. (1983), "New UBVRI photometry for 900 supergiants", Astrophysical Journal Supplement Series, 52: 7, Bibcode:1983ApJS...52....7F, doi:10.1086/190856.
  3. Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
  4. 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.
  5. Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x.
  6. Venn, Kim A. (August 1995), "Atmospheric Parameters and LTE Abundances for 22 Galactic, A-Type Supergiants", Astrophysical Journal Supplement, 99: 659, Bibcode:1995ApJS...99..659V, doi:10.1086/192201.
  7. McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  8. Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247.
  9. Royer, F.; et al. (January 2012), "Rotational velocities of A-type stars. I. Measurement of v sin i in the southern hemisphere", Astronomy and Astrophysics, 381: 105–121, arXiv:astro-ph/0110490, Bibcode:2002A&A...381..105R, doi:10.1051/0004-6361:20011422.
  10. "ksi01 Sgr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-05.
  11. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
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