X Sagittarii

X Sagittarii is a bright giant Cepheid variable star in the constellation Sagittarius.

X Sagittarii
Location of X Sagittarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Sagittarius
Right ascension  17h 47m 33.62432s[1]
Declination −27° 49′ 50.8330″[1]
Apparent magnitude (V) 4.54[2]
Characteristics
Spectral type F7II[3]
U−B color index +0.50[2]
B−V color index +0.80[2]
Variable type Cepheid[4]
Astrometry
Radial velocity (Rv)-10.10[5] km/s
Proper motion (μ) RA: -4.08[1] mas/yr
Dec.: -10.05[1] mas/yr
Parallax (π)3.31 ± 0.26[1] mas
Distance990 ± 80 ly
(300 ± 20 pc)
Absolute magnitude (MV)-2.85[6]
Details
Mass6.31[7] M☉
Luminosity2,647[7] L☉
Surface gravity (log g)1.77[8] cgs
Temperature6,305[7] K
Metallicity [Fe/H]-0.01[6] dex
Rotational velocity (v sin i)27.1[9] km/s
Other designations
3 Sagittarii, X Sgr, CD-27°11930, FK5 1464, GC 24135, GSC 06836-00118, HIP 87072, HR 6616, HD 161592, SAO 185755
Database references
SIMBADdata

This variable star changes in apparent magnitude from 4.90 to 4.20 magnitude with a period of 7.01 days. Its change in brightness is accompanied by a change in spectral classification, from G2 to F5.[4] It is approximately 990 light years away based on parallax.[1]

References
  1. Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
  2. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
  4. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....1.2025S.
  5. Kharchenko, N.V.; Scholz, R.-D.; Piskunov, A.E.; Röser, S.; Schilbach, E. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ∼55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776.
  6. 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. Vizier catalog entry
  7. Hohle, M.M.; Neuhäuser, R.; Schutz, B.F. (2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten. 331 (4): 349. arXiv:1003.2335. Bibcode:2010AN....331..349H. doi:10.1002/asna.200911355. Vizier catalog entry
  8. Soubiran, Caroline; Le Campion, Jean-François; Brouillet, Nathalie; Chemin, Laurent (2016). "The PASTEL catalogue: 2016 version". Astronomy & Astrophysics. 591: A118. arXiv:1605.07384. Bibcode:2016A&A...591A.118S. doi:10.1051/0004-6361/201628497.
  9. De Medeiros, J. R.; Mayor, M. (1999). "A catalog of rotational and radial velocities for evolved stars". Astronomy and Astrophysics Supplement Series. 139 (3): 433. arXiv:astro-ph/0608248. Bibcode:1999A&AS..139..433D. doi:10.1051/aas:1999401. Vizier catalog entry


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