Tau3 Gruis

Tau³ Gruis is a solitary^[7] star in the southern constellation of Grus. Its apparent magnitude is 5.71,^[2] which is bright enough to be visible to the naked eye as a dim, white-hued star. The star is located around 265 light-years (81 pc) distant from the Sun based on parallax, and it is drifting further away with a radial velocity of 6 km/s.^[4]

For other stars with this Bayer designation, see τ Gruis.

Tau³ Gruis

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Grus
Right ascension	22h 56m 47.80007s[1]
Declination	−47° 58′ 09.1992″[1]
Apparent magnitude (V)	5.71[2]
Characteristics
Spectral type	kA5hA7mF2[3]
U−B color index	+0.17[2]
B−V color index	+0.22[2]
Astrometry
Radial velocity (Rv)	6.3±0.6[4] km/s
Proper motion (μ)	RA: −24.942[1] mas/yr Dec.: +2.848[1] mas/yr
Parallax (π)	12.3180 ± 0.1170 mas[1]
Distance	265 ± 3 ly (81.2 ± 0.8 pc)
Absolute magnitude (MV)	+1.36[5]
Details
Radius	2.88+0.13 −0.18[1] R☉
Luminosity	26.8+0.3 −0.3[1] L☉
Temperature	7,735+406 −158[1] K
Other designations
τ Gru, CD−48°14364, FK5 3832, HD 216823, HIP 113307, HR 8722, SAO 231364[6]
Database references
SIMBAD	data

This is an Am star^[8] with a stellar classification of kA5hA7mF2.^[3] This notation indicates the spectrum displays the calcium K-line of an A5 star, the hydrogen lines of an A7 star, and the metal lines of an F2 star.^[9] It has 2.9^[1] times the Sun's radius and is radiating 27^[1] times the luminosity of the Sun from its photosphere at an effective temperature of around 7,735 K.^[1]

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
2. Feinstein, A. (1974), "Photoelectric UBVRI observations of Am stars", Astronomical Journal, 79: 1290, Bibcode:1974AJ.....79.1290F, doi:10.1086/111675.
3. Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182
4. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
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, S2CID 119257644.
6. "tau03 Gru". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-24.{{cite web}}: CS1 maint: postscript (link)
7. 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, S2CID 14878976.
8. Renson, P.; Manfroid, J. (2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics, 498 (3): 961–966, Bibcode:2009A&A...498..961R, doi:10.1051/0004-6361/200810788.
9. Gray, Richard O.; Corbally, J. (2009), Stellar Spectral Classification, Princeton University Press, p. 178, ISBN 978-0691125114.