Tau Boötis (τ Boo, τ Boötis) is an F-type main-sequence star approximately 51 light-years away in the constellation of Boötes. The system is also a binary star system, with the secondary star being a red dwarf. As of 1999, an extrasolar planet has been confirmed to be orbiting the primary star.
The system is a binary. The primary component is a yellow-white dwarf (spectral type F7 V) and secondary is a dim red dwarf (spectral type M2 V). The system is relatively nearby, distance being about 51 light years. The primary star should be easily visible to the unaided eye under dark skies.
The primary star, Tau Boötis A is a yellow-white dwarf. It is 20% more massive than our Sun and thus is somewhat brighter and hotter. It has a radius 1.9 times solar, and is probably about 1.3 billion years old. Since it is more massive than the Sun, its lifespan is shorter - less than 6 billion years. Tau Bootis is the first star apart from the sun to be observed changing the polarity of its magnetic field. It is also listed as a suspected variable star.
In 1996 a planet, designated as Tau Boötis b, was discovered orbiting the primary star. There are also some indications of another, more distant, planet orbiting the star. In an unusual case of role-reversal, it appears that Tau Boötis' rotation has been tidally locked to Tau Boötis b. The planet was discovered by a team of astronomers led by Geoff Marcy and R. Paul Butler.
(in order from star)
|b||6±0.28 MJ||0.0481 ± 0.028||3.312463 ± 0.000014||0.023 ± 0.015||44.5 ± 1.5°||—|
The planet and its host star is one of the planetary systems selected by the International Astronomical Union as part of their public process for giving proper names to exoplanets and their host star (where no proper name already exists). The process involved public nomination and voting for the new names, and the IAU planned to announce the new names in mid-December 2015. However, the IAU annulled the vote as the winning name ("Shri Ram Matt" for the star, "Bhagavatidevi" for the planet) was judged not to conform with the IAU rules for naming exoplanets. These names garnered the vast majority of the votes cast for the system, and indeed, also making up a significant proportion of votes cast in the entire contest.
- 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. Vizier catalog entry
- Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics 352: 495–507, Bibcode:1999A&A...352..495M
- Strassmeier, Klaus G. (September 2009), "Starspots", The Astronomy and Astrophysics Review 17 (3): 251–308, Bibcode:2009A&ARv..17..251S, doi:10.1007/s00159-009-0020-6
- Mamajek, Eric E.; Hillenbrand, Lynne A. (2008). "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics". The Astrophysical Journal 687 (2): 1264–1293. arXiv:0807.1686. Bibcode:2008ApJ...687.1264M. doi:10.1086/591785.
- Donati, J.-F.; et al. (2008). "Magnetic cycles of the planet-hosting star Tau Boötis". Monthly Notices of the Royal Astronomical Society 385 (3): 1179–1185. arXiv:0802.1584. Bibcode:2008MNRAS.385.1179D. doi:10.1111/j.1365-2966.2008.12946.x.
- Butler, R. Paul; et al. (1997). "Three New 51 Pegasi Type Planets". The Astrophysical Journal Letters 474 (2): L115–L118. Bibcode:1997ApJ...474L.115B. doi:10.1086/310444.
- Walker, G. A. H.; et al. (2008). "MOST detects variability on tau Bootis possibly induced by its planetary companion". Astronomy and Astrophysics 482 (2): 691–697. arXiv:0802.2732. Bibcode:2008A&A...482..691W. doi:10.1051/0004-6361:20078952.
- Butler, R. P.; et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal 646 (1): 505–522. arXiv:astro-ph/0607493. Bibcode:2006ApJ...646..505B. doi:10.1086/504701.
- "NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars". International Astronomical Union. 9 July 2014. Retrieved 8 January 2016.
- "The ExoWorlds". NameExoWorlds. International Astronomical Union. n.d. Retrieved 8 January 2016.
- "The Process". NameExoWorlds. International Astronomical Union. 30 November 2015. Retrieved 8 January 2016.
- "The Statistics". NameExoWorlds. International Astronomical Union. n.d. Retrieved 8 January 2016.
- "Final Results of NameExoWorlds Public Vote Released". International Astronomical Union. 15 December 2015. Retrieved 8 January 2016.
- "VizieR: HR 5185". Centre de Données astronomiques de Strasbourg. Retrieved 2009-05-15.
- "VizieR: CCDM J13473+1727". Centre de Données astronomiques de Strasbourg. Retrieved 2009-05-15.
- "Aladin Previewer: Tau Boötis". Centre de Données astronomiques de Strasbourg. Retrieved 2009-05-15.
- Schirber, Michael (23 May 2005). "Role Reversal: Planet Controls a Star". SPACE.com. Retrieved 2008-06-25.
- "Notes for star Tau Boo". The Extrasolar Planets Encyclopaedia. Retrieved 2008-06-25.
- "Tau Boötis 2". SolStation. Retrieved 2008-06-25.
- "Tau Bootis". The Planet Project. Retrieved 2008-06-25.