Tau3 Eridani

τ³ Eridani
Observation data; Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Eridanus
Right ascension	03h 02m 23.49939s
Declination	−23° 37′ 28.0936″
Apparent magnitude (V)	4.10
Characteristics
Spectral type	A3 IV-V
U−B color index	+0.08
B−V color index	+0.16
Astrometry
Radial velocity (Rv)	−9.8 km/s
Proper motion (μ)	RA: −147.25 mas/yr ; Dec.: −55.28 mas/yr
Parallax (π)	36.80 ± 0.18 mas
Distance	88.6 ± 0.4 ly ; (27.2 ± 0.1 pc)
Absolute magnitude (MV)	+1.91
Details
Mass	1.78 M☉
Radius	1.9 R☉
Luminosity	13.7 L☉
Surface gravity (log g)	4.17 cgs
Temperature	8,251±281 K
Metallicity [Fe/H]	−0.21 dex
Rotational velocity (v sin i)	133 km/s
Age	476 Myr
Other designations
	τ3 Eridani, τ3 Eri, 11 Eridani, CD-24° 1387, HD 18978, HIP 14146, HR 919, SAO 168249.
Database references
SIMBAD	data

Tau³ Eridani, Latinized from τ³ Eridani, is a star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 4.10.^[2] Using the parallax method,^[1] the distance to this star can be estimated as 88.6 light years. In 2001 it was reported as a candidate Vega-like star, meaning it appears to radiate an infrared excess from an orbiting circumstellar disk.^[11] However, this has not been confirmed.^[12]

This is an A-type star with a stellar classification of A3 IV-V.^[3] The luminosity class of IV-V indicates the spectrum displays traits intermediate between a main sequence and subgiant star. It is around 476^[6] million years old and is spinning rapidly with a projected rotational velocity of 133 km/s.^[9] This is creating an equatorial bulge that might be 7% wider than the polar radius.^[13] Tau³ Eridani has 178%^[6] of the Sun's mass and nearly double the radius of the Sun.^[7] The star shines with 13.7 times the solar luminosity from an outer atmosphere at an effective temperature of 8,251 K.^[6]

References

^ ^a ^b ^c ^d ^e ^f van Leeuwen, F. (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.
^ ^a ^b ^c ^d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
^ ^a ^b ^c Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992.
^ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W.
^ 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.
^ ^a ^b ^c ^d ^e ^f ^g David, Trevor J.; Hillenbrand, Lynne A. (May 2015), "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 38, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607, 146.
^ ^a ^b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
^ McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
^ ^a ^b Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298.
^ "tau03 Eri". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-10-13.{{cite web}}: CS1 maint: postscript (link)
^ Song, Inseok; et al. (January 2001), "Ages of A-Type Vega-like Stars from uvbyβ Photometry", The Astrophysical Journal, 546 (1): 352–357, arXiv:astro-ph/0010102, Bibcode:2001ApJ...546..352S, doi:10.1086/318269, S2CID 18154947.
^ Gáspár, András; et al. (May 2013), "The Collisional Evolution of Debris Disks", The Astrophysical Journal, 768 (1): 29, arXiv:1211.1415, Bibcode:2013ApJ...768...25G, doi:10.1088/0004-637X/768/1/25, S2CID 119295265, 25.
^ Van Belle, Gerard T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474.