Theta Leporis

Theta Leporis, Latinized from θ Leporis, is a solitary,[9] white-hued star in the southern constellation of Lepus. It has an apparent visual magnitude of 4.67,[2] making it bright enough to be viewed with the naked eye. Based upon an annual parallax shift of 18.88 mas as measured from Earth,[1] the system is located roughly 173 light years from the Sun. The star made its closest approach about 1.6 million years ago when it came within 29 ly (9.0 pc) of the Sun.[10]

Theta Leporis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lepus
Right ascension 06h 06m 09.32339s[1]
Declination −14° 56′ 06.9188″[1]
Apparent magnitude (V) 4.67[2]
Characteristics
Spectral type A0 V[3]
U−B color index +0.00[2]
B−V color index +0.05[2]
Astrometry
Radial velocity (Rv)+32.0[4] km/s
Proper motion (μ) RA: -17.61[1] mas/yr
Dec.: +12.79[1] mas/yr
Parallax (π)18.88 ± 0.54 mas[1]
Distance173 ± 5 ly
(53 ± 2 pc)
Absolute magnitude (MV)+1.05[5]
Details
Mass2.35±0.03[6] M☉
Luminosity41[6] L☉
Surface gravity (log g)4.12[7] cgs
Temperature10,453±355[7] K
Rotational velocity (v sin i)246[7] km/s
Age207[7] Myr
Other designations
θ Lep, 18 Lep, BD−14° 1331, FK5 2466, GC 7742, HD 41695, HIP 28910, HR 2155, SAO 151110[8]
Database references
SIMBADdata

This is an ordinary A-type main-sequence star with a stellar classification of A0 V[3] and an age of about 207 million years.[7] It is rotating rapidly with a projected rotational velocity of 207 km/s.[7] This is giving the star an oblate shape with an equatorial bulge that is an estimated 10% larger than the polar radius.[11] It has an estimated 2.35[6] times the mass of the Sun and is radiating 41[6] times the Sun's luminosity from its photosphere at an effective temperature of around 10,453 K.[7]

References
  1. 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.
  2. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  3. Houk, N. (1988), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
  4. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 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. Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  7. David, Trevor J.; Hillenbrand, Lynne A. (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): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
  8. "tet Lep". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-18.{{cite web}}: CS1 maint: postscript (link)
  9. 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.
  10. Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics, 575: 13, arXiv:1412.3648, Bibcode:2015A&A...575A..35B, doi:10.1051/0004-6361/201425221, S2CID 59039482, A35.
  11. Belle, G. 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.
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