Tau Puppis

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]

  1. ^ a b c d e Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference mnassa31_69 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1978 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference gcrv1953 was invoked but never defined (see the help page).
  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. ^ Cite error: The named reference Cardini2005 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference aaa442_1_365 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Spencer_Jones_1928 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference Luck2015 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference lang2006 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference aaa382_1016 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference aaa431_773 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference mnras414_1_418 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference csiro was invoked but never defined (see the help page).