Tau1 Lupi

Tau1 Lupi, Latinized from τ1 Lupi, is a solitary[12] star in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 4.5.[2] Based upon an annual parallax shift of only 2.99 mas as seen from Earth, it is located about 1,090 light years from the Sun. Tau1 Lupi may be a runaway star[10] having a peculiar velocity of 32.6±3.6 km/s.[3] It is a member of the Upper-Centaurus Lupus sub-group of the nearby Sco OB2 association.[13]

For other stars with this Bayer designation, see τ Lupi.
Tau1 Lupi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lupus
Right ascension  14h 26m 08.22424s[1]
Declination −45° 13′ 17.1315″[1]
Apparent magnitude (V) 4.546[2]
Characteristics
Spectral type B2 IV[3][2]
B−V color index −0.146[2]
Variable type β Cep[4]
Astrometry
Radial velocity (Rv)−21.5±2.8[3] km/s
Proper motion (μ) RA: −13.09[1] mas/yr
Dec.: −14.67[1] mas/yr
Parallax (π)2.99 ± 0.21[1] mas
Distance1,090 ± 80 ly
(330 ± 20 pc)
Absolute magnitude (MV)−3.05[5]
Details
Mass9.98±0.63[2] M☉
Radius7.1[6] R☉
Luminosity3,831[7] L☉
Luminosity (bolometric)11,321[2] L☉
Temperature15,273[7] K
Metallicity [Fe/H]−0.39±0.16[8] dex
Rotational velocity (v sin i)30[9] km/s
Age20.8±0.9[10] Myr
Other designations
τ1 Lup, CD−44° 9322, FK5 1377, HD 126341, HIP 70574, HR 5395, SAO 224919.[11]
Database references
SIMBADdata

This is a B-type subgiant star with a stellar classification of B2 IV.[3][2] It was determined to be a Beta Cephei variable based on observations during 1955 at the Cape Observatory.[14] Tau1 Lupi shows a steady period of 0.17736934 days, corresponding to a frequency of 5.637953 cycles per day, with an amplitude of 0.035 in visual magnitude.[4][15] It has around 10[2] times the mass of the Sun and 7[6] times the Sun's radius.

The star shows an infrared excess, which is unusual for a non-emission star of this class. The inner edge of the dust lies at a distance of 980 AU from the star with a temperature of 190 K, and it extends outward to as much as 50,000 AU where the temperature drops to 40 K. This optically thin dust is not related to the pulsational behavior of the star.[9]

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. 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.
  3. Bobylev, V. V.; Bajkova, A. T. (August 2013), "Galactic kinematics from a sample of young massive stars", Astronomy Letters, 39 (8): 532–549, arXiv:1307.1677, Bibcode:2013AstL...39..532B, doi:10.1134/S106377371308001X.
  4. Cuypers, J. (June 1987), "New observations and frequency analysis of the Beta Cephei star Tau1 Lupi", Astronomy and Astrophysics Supplement Series, 69 (3): 445–449, Bibcode:1987A&AS...69..445C.
  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.
  6. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (3rd ed.), 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  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. Daszyńska-Daszkiewicz, J.; Niemczura, E. (April 2005), "Metallicity of mono- and multiperiodic β Cephei stars", Astronomy and Astrophysics, 433 (3): 1031–1035, arXiv:astro-ph/0410442, Bibcode:2005A&A...433.1031D, doi:10.1051/0004-6361:20040397.
  9. Aerts, C.; De Boeck, I.; Malfait, K.; De Cat, P. (July 1999), "HD 42927 and HD 126341: two pulsating B stars surrounded by circumstellar dust", Astronomy and Astrophysics, 347: 524–531, Bibcode:1999A&A...347..524A.
  10. 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.
  11. "tau01 Lup -- Variable Star of beta Cep type", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-03-10.
  12. 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.
  13. de Geus, E. J.; et al. (June 1989), "Physical parameters of stars in the Scorpio-Centaurus OB association", Astronomy and Astrophysics, 216 (1–2): 44–61, Bibcode:1989A&A...216...44D.
  14. Pagel, B. E. J. (1956), "Results of a search for bright β Cephei variables in the southern sky", Monthly Notices of the Royal Astronomical Society, 116: 10, Bibcode:1956MNRAS.116...10P, doi:10.1093/mnras/116.1.10.
  15. Stankov, Anamarija; Handler, Gerald (2005), "Catalog of Galactic β Cephei Stars", The Astrophysical Journal Supplement Series, 158 (2): 193–216, arXiv:astro-ph/0506495, Bibcode:2005ApJS..158..193S, doi:10.1086/429408, ISSN 0067-0049.
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