Astronomy:Tau2 Lupi

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Short description: Binary star system in the constellation Lupus


Tau2 Lupi
Observation data
Equinox J2000.0]] (ICRS)
Constellation Lupus
Right ascension  14h 26m 10.81378s[1]
Declination −45° 22′ 45.4023″[1]
Apparent magnitude (V) 4.34[2] (4.93 + 5.55)[3]
Characteristics
Spectral type F4 IV + A7:[3]
U−B color index +0.16[2]
B−V color index +0.43[2]
Astrometry
Radial velocity (Rv)−0.60±1.60[4] km/s
Proper motion (μ) RA: +14.62[1] mas/yr
Dec.: −7.33[1] mas/yr
Parallax (π)10.22 ± 0.31[1] mas
Distance319 ± 10 ly
(98 ± 3 pc)
Absolute magnitude (MV)−0.62[5]
Orbit[6]
Period (P)26.2 yr
Semi-major axis (a)0.125″
Eccentricity (e)0.94
Inclination (i)56.0°
Longitude of the node (Ω)175.7°
Periastron epoch (T)1969.1
Argument of periastron (ω)
(secondary)
191.0°
Details
Luminosity150[5] L
Rotational velocity (v sin i)0[7] km/s
Other designations
τ2 Lup, CD−44° 9323, HD 126354, HIP 70576, HR 5396, SAO 224920.[8]
Database references
SIMBADdata

Tau2 Lupi, Latinized from τ2 Lup, is a binary star[3] system in the constellation Lupus. It is visible to the naked eye with a combined apparent visual magnitude of 4.34.[2] Based upon an annual parallax shift of 10.22[1] mas as seen from Earth, it is located around 319 light years from the Sun. The two components orbit each other with a period of 26.2 years and a high eccentricity of 0.94.[6] The brighter component is a magnitude 4.93 subgiant star with a stellar classification of F4 IV. Its companion is an A-type star with visual magnitude 5.55 and class A7:.[3]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode1986EgUBV........0M. 
  3. 3.0 3.1 3.2 3.3 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  4. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode2012A&A...546A..61D. 
  5. 5.0 5.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  6. 6.0 6.1 Heintz, W. D. (August 1986), "Orbits of 20 visual binaries", Astronomy and Astrophysics Supplement Series 65 (2): 411–417, Bibcode1986A&AS...65..411H. 
  7. Uesugi, Akira; Fukuda, Ichiro (1970), "Catalogue of rotational velocities of the stars", Contributions from the Institute of Astrophysics and Kwasan Observatory (University of Kyoto), Bibcode1970crvs.book.....U. 
  8. "tau02 Lup". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=tau02+Lup.