HR 6875

HR 6875, previously known as Sigma Telescopii, is a single[10] star in the constellation Corona Australis. It has a blue-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.24.[2] This object is located at a distance of approximately 550 light years from the Sun based on parallax.[1] It is listed as a member of the Sco OB2 association.[7]

HR 6875
Observation data
Epoch J2000      Equinox J2000
Constellation Corona Australis
Right ascension  18h 24m 18.24148s[1]
Declination −44° 06′ 36.9008″[1]
Apparent magnitude (V) 5.24[2]
Characteristics
Spectral type B3 V[3]
B−V color index −0.163±0.004[2]
Astrometry
Radial velocity (Rv)+0.00±7.40[2] km/s
Proper motion (μ) RA: −2.949[1] mas/yr
Dec.: −23.107[1] mas/yr
Parallax (π)5.9327 ± 0.2341[1] mas
Distance550 ± 20 ly
(169 ± 7 pc)
Absolute magnitude (MV)−0.63[2]
Details
Mass6.2±0.1[4] M☉
Radius3.9[5] R☉
Luminosity (bolometric)1,098[6] L☉
Temperature20,350[6] K
Rotational velocity (v sin i)248±12[7] km/s
Age103[8] Myr
Other designations
CD−44° 12569, FK5 3461, HD 168905, HIP 90200, HR 6875, SAO 228982, WDS J18243-4407A[9]
Database references
SIMBADdata

This is a hot B-type main-sequence star with a stellar classification of B3 V.[3] It is around 103[8] million years old and is spinning rapidly with a projected rotational velocity of 248 km/s or perhaps higher.[7] The star has six[4] times the mass of the Sun and about four[5] times the Sun's radius. It is radiating more than a thousand[6] times the luminosity of the Sun from its photosphere at an effective temperature of 20,350 K.[6]

A magnitude 10.13 visual companion is located at an angular separation of 74″ along a position angle of 162°.[11]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. 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.
  3. Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  4. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (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.
  5. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (Third ed.), 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  6. Hohle, M. M.; et al. (April 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.
  7. Brown, A. G. A.; Verschueren, W. (1997), "High S/N Echelle spectroscopy in young stellar groups. II. Rotational velocities of early-type stars in SCO OB2", Astronomy and Astrophysics, 319: 811, arXiv:astro-ph/9608089, Bibcode:1997A&A...319..811B.
  8. Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035.
  9. "HD 168905". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-14.
  10. 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.
  11. Mason, B. D.; et al. (2014), The Washington Visual Double Star Catalog, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22
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