Tau Puppis
Location of τ Puppis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Puppis
Right ascension 06h 49m 56.16846s[1]
Declination −50° 36′ 52.4437″[1]
Apparent magnitude (V) +2.95[2]
Characteristics
Spectral type K1 III[3]
U−B color index +1.195[2]
B−V color index +1.20[2]
Astrometry
Radial velocity (Rv)+36.4[4] km/s
Proper motion (μ) RA: +34.36[1] mas/yr
Dec.: −69.11[1] mas/yr
Parallax (π)18.7577 ± 0.3475 mas[5]
Distance174 ± 3 ly
(53.3 ± 1.0 pc)
Absolute magnitude (MV)−0.80[6]
Orbit[7][8]
Period (P)1,066.0±4.0 d
Semi-major axis (a)7.15±0.25 mas
Eccentricity (e)0.088±0.045
Inclination (i)80.20 ± 6.10°
Longitude of the node (Ω)2.90 ± 6.20°
Periastron epoch (T)2,420,992.8±94.5 HJD
Argument of periastron (ω)
(secondary)		64.00°
Details
Mass3.19[9] M☉
Radius27[10] R☉
Temperature4,489±33[9] K
Rotational velocity (v sin i)2.2[11] km/s
Age540[9] Myr
Other designations
Tau Pup, τ Pup, CPD−50° 1070, FK5 263, HD 50310, HIP 32768, HR 2553, SAO 234735, PPM 335509[12]
Database references
SIMBADdata

Tau Puppis, Latinized from τ Puppis, is a star in the southern constellation of Puppis, near the southern constellation boundary with Carina. It is visible to the naked with an apparent visual magnitude of +2.95[2] and is located at a distance of about 182 light-years (56 parsecs) from Earth.[1] The variable radial velocity of this system was detected by H. D. Curtis and H. K. Palmer in 1908, based on observations made at the D. O. Mills Observatory.[8] It is a spectroscopic binary star system, with the presence of the secondary component being revealed by the shifts of absorption lines in the spectrum resulting from the Doppler effect. The two components orbit each other with a period of 1,066.0 days (2.9 years) and a low eccentricity of 0.090.[7]

The primary component of this system has a stellar classification of K1 III.[3] A luminosity class 'III' indicates this has expanded into a giant star after exhausting the supply of hydrogen at its core and evolving away from the main sequence of stars like the Sun. The interferometry-measured angular diameter of this star, after correcting for limb darkening, is 4.49 ± 0.07 mas,[13] which, at its estimated distance, equates to a physical radius of about 27 times the radius of the Sun.[10] It appears to be rotating slowly, with a projected rotational velocity of 2.2 km s−1.[11] This gives a lower bound on the azimuthal velocity of rotation along the star's equator. Tau Puppis is radiating energy from its outer envelope at an effective temperature of around 4,500 K,[14] giving it the orange hue of a cool, K-type star.[15]

References

  1. 1 2 3 4 5 van Leeuwen, F. (November 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, S2CID 18759600
  2. 1 2 3 4 Cousins, A. W. J. (1972), "UBV Photometry of Some Very Bright Stars", Monthly Notes of the Astronomical Society of Southern Africa, 31: 69, Bibcode:1972MNSSA..31...69C
  3. 1 2 Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H
  4. ↑ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication. Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
  5. ↑ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  6. ↑ Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics, 430: 303–311, arXiv:astro-ph/0409683, Bibcode:2005A&A...430..303C, doi:10.1051/0004-6361:20041440, S2CID 12136256.
  7. 1 2 Jancart, S.; et al. (October 2005), "Astrometric orbits of SB^9 stars", Astronomy and Astrophysics, 442 (1): 365–380, arXiv:astro-ph/0507695, Bibcode:2005A&A...442..365J, doi:10.1051/0004-6361:20053003, S2CID 15123997
  8. 1 2 Spencer Jones, H. (June 1928), "The orbits of four long-period spectroscopic binaries", Monthly Notices of the Royal Astronomical Society, 88 (8): 644, Bibcode:1928MNRAS..88..644S, doi:10.1093/mnras/88.8.644.
  9. 1 2 3 Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114, 88.
  10. 1 2 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
  11. 1 2 Costa, J. M.; et al. (February 2002), "The tidal effects on the lithium abundance of binary systems with giant component", Astronomy and Astrophysics, 382 (3): 1016–1020, arXiv:astro-ph/0111539, Bibcode:2002A&A...382.1016C, doi:10.1051/0004-6361:20011676, S2CID 17024265{{citation}}: CS1 maint: multiple names: authors list (link)
  12. ↑ "* tau Pup". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-01-25.
  13. ↑ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039
  14. ↑ Pérez Martínez, M. Isabel; Schröder, K.-P.; Cuntz, M. (June 2011), "The basal chromospheric Mg II h+k flux of evolved stars: probing the energy dissipation of giant chromospheres", Monthly Notices of the Royal Astronomical Society, 414 (1): 418–427, arXiv:1102.4832, Bibcode:2011MNRAS.414..418P, doi:10.1111/j.1365-2966.2011.18421.x, S2CID 59268230
  15. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2013-12-03, retrieved 2012-01-16
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