Astronomy:Tau Puppis

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Short description: Orange-hued giant star in the southern constellation of Puppis
Tau Puppis
Puppis IAU.svg
Red circle.svg
Location of τ Puppis (circled)
Observation data
Equinox J2000.0]] (ICRS)
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[5] mas
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. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (November 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 Cousins, A. W. J. (1972), "UBV Photometry of Some Very Bright Stars", Monthly Notes of the Astronomical Society of Southern Africa 31: 69, Bibcode1972MNSSA..31...69C 
  3. 3.0 3.1 Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode1978mcts.book.....H 
  4. Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication (Carnegie Institution of Washington). Bibcode1953GCRV..C......0W. 
  5. Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  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, doi:10.1051/0004-6361:20041440, Bibcode2005A&A...430..303C. 
  7. 7.0 7.1 Jancart, S. et al. (October 2005), "Astrometric orbits of SB^9 stars", Astronomy and Astrophysics 442 (1): 365–380, doi:10.1051/0004-6361:20053003, Bibcode2005A&A...442..365J 
  8. 8.0 8.1 Spencer Jones, H. (June 1928), "The orbits of four long-period spectroscopic binaries", Monthly Notices of the Royal Astronomical Society 88 (8): 644, doi:10.1093/mnras/88.8.644, Bibcode1928MNRAS..88..644S. 
  9. 9.0 9.1 9.2 Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal 150 (3): 23, doi:10.1088/0004-6256/150/3/88, 88, Bibcode2015AJ....150...88L. 
  10. 10.0 10.1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 . The radius (R*) is given by:
    [math]\displaystyle{ \begin{align} 2\cdot R_* & = \frac{(10^{-3}\cdot 56\cdot 4.49)\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\ & \approx 54\cdot R_{\bigodot} \end{align} }[/math]
  11. 11.0 11.1 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, doi:10.1051/0004-6361:20011676, Bibcode2002A&A...382.1016C 
  12. "* tau Pup". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+tau+Pup. 
  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, doi:10.1051/0004-6361:20042039, Bibcode2005A&A...431..773R 
  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, doi:10.1111/j.1365-2966.2011.18421.x, Bibcode2011MNRAS.414..418P 
  15. "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16 

External links