Theta Tauri

θ¹ Tauri
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Taurus
Right ascension 04h 28m 34.49603s[1]
Declination +15° 57′ 43.8494″[1]
Apparent magnitude (V) +3.84
Characteristics
Spectral type G9 III Fe-0.5[2]
Astrometry
Parallax (π)21.4183 ± 0.3731[3] mas
Distance152 ± 3 ly
(46.7 ± 0.8 pc)
Absolute magnitude (MV)+0.416[4]
Orbit[5]
Period (P)5,997 days
Eccentricity (e)0.64
Semi-amplitude (K1)
(primary)		8.39 km/s
Details
Mass2.67[6] M☉
Radius10.55[6] R☉
Luminosity71[6] L☉
Surface gravity (log g)3.21[6] cgs
Temperature5,080[6] K
Metallicity [Fe/H]+0.14[6] dex
Rotational velocity (v sin i)1.40[6] km/s
Age510[6] Myr
Other designations
Chamukuy, 77 Tauri, BD+15 631, HD 28307, HIP 20885, HR 1411, SAO 93955.
Database references
SIMBADdata
θ² Tauri
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Taurus
Right ascension 04h 28m 39.74070s[1]
Declination +15° 52′ 15.1745″[1]
Apparent magnitude (V) +3.35 - 3.42[7]
Characteristics
Spectral type A7 III[8]
Variable type δ Scuti[7]
Astrometry
Parallax (π)20.8354 ± 0.3731[9] mas
Distance157 ± 3 ly
(48.0 ± 0.9 pc)
Absolute magnitude (MV)+0.30/+1.44[10]
Orbit[10]
Period (P)140.7302 days
Semi-major axis (a)18.91″
Eccentricity (e)0.7360
Inclination (i)47.8°
Semi-amplitude (K1)
(primary)		32.95 km/s
Semi-amplitude (K2)
(secondary)		43.68 km/s
Details
Ba
Mass2.86[11] M☉
Radius4.4[11] R☉
Luminosity59[10] L☉
Surface gravity (log g)3.6[11] cgs
Temperature7,800[11] K
Rotational velocity (v sin i)68.4[10] km/s
Bb
Mass2.16[11] M☉
Radius2.7[11] R☉
Luminosity21[10] L☉
Temperature7,800[10] K
Rotational velocity (v sin i)113[10] km/s
Age650[10] Myr
Other designations
78 Tauri, BD+15 632, HD 28319, HIP 20894, HR 1412, SAO 93957.
Database references
SIMBADdata

Theta Tauri (θ Tauri, abbreviated Tet Tau, θ Tau) is a wide double star in the constellation of Taurus and a member of the Hyades open cluster.

θ Tauri is composed of two 3rd magnitude stars, designated Theta¹ Tauri and Theta² Tauri, or alternatively Theta Tauri A and B, respectively. They are separated by 5.62 arcminutes (0.094°) on the sky. Based upon parallax measurements, Theta¹ Tauri is located at a distance of 152 ly (47 pc), while Theta² Tauri is at a distance of 157 light-years (48 parsecs). θ Tauri A and B are both spectroscopic binaries; the four components are designated Theta Tauri Aa (also named Chamukuy), Ab, Ba and Bb.

Nomenclature

Hyades cluster, centred on the θ Tauri pair

θ Tauri (Latinised to Theta Tauri) is the double star's Bayer designation; θ¹ Tauri and θ² Tauri those of its two constituents. The designations of the two constituents as Theta Tauri A and B, and those of the four components - Theta Tauri Aa, Ab, Ba and Bb - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[12]

In the mythology of the Maya peoples, Theta Tauri is known as Chamukuy, meaning a small bird in the Yucatec Maya language.[13] In 2016, the IAU organized a Working Group on Star Names (WGSN)[14] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[15] It approved the name Chamukuy for the component Theta Tauri Aa on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.[16]

In Chinese, 畢宿 (Bì Xiù), meaning Net, refers to an asterism consisting of Theta² Tauri, Epsilon Tauri (named Ain), Delta³ Tauri, Delta¹ Tauri, Gamma Tauri, Alpha Tauri (Aldebaran), 71 Tauri and Lambda Tauri.[17] Consequently, Theta² Tauri itself is known as 畢宿六 (Bì Xiù liù), "the Sixth Star of Net".[18]

Properties

Theta Tauri A is the dimmer constituent. Its primary component, Theta Tauri Aa, is an orange K-type giant with an apparent magnitude of +3.84. The secondary, Theta Tauri Ab, is of the 7th-magnitude. It has a mass of 1.31 M☉ and orbits the primary every 16.26 years on a fairly eccentric (at 0.570) orbit.[19]

Theta Tauri B has a mean apparent magnitude of +3.40. It is classified as a Delta Scuti type variable star and its brightness varies from magnitude +3.35 to +3.42 with a period of 1.82 hours.[20] Its primary component, Theta Tauri Ba, is a white A-type giant. The secondary, Theta Tauri Bb, is of the 6th magnitude and is 0.005 arcseconds, or at least 2 AU, distant. It completes an orbit once every 141 days.

References

  1. 1 2 3 4 van Leeuwen, F. (November 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
  2. ↑ . Bibcode:1989ApJS...71..245K. Missing or empty |title= (help)
  3. ↑ 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.
  4. ↑ Böhm-Vitense, Erika; et al. (December 2000), "Ultraviolet Emission Lines in BA and Non-BA Giants", The Astrophysical Journal, 545 (2): 992–999, Bibcode:2000ApJ...545..992B, doi:10.1086/317850.
  5. ↑ . Bibcode:2007A&A...473..829M. doi:10.1051/0004-6361:20078007. Missing or empty |title= (help)
  6. 1 2 3 4 5 6 7 8 . Bibcode:2015A&A...574A..50J. Missing or empty |title= (help)
  7. 1 2 Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally Published In: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
  8. ↑ . Bibcode:1978rmsa.book.....M. Missing or empty |title= (help)
  9. ↑ 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.
  10. 1 2 3 4 5 6 7 8 . arXiv:1010.5643. Bibcode:2011A&A...525A..50T. doi:10.1051/0004-6361/201015166. Missing or empty |title= (help)
  11. 1 2 3 4 5 6 . Bibcode:2017MNRAS.465.1181L. Missing or empty |title= (help)
  12. ↑ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  13. ↑ Susan Milbrath: Star gods of the Maya: astronomy in art, folklore, and calendars on p. 253, University of Texas Press, Texas 1999, 2010.
  14. ↑ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  15. ↑ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  16. ↑ "Naming Stars". IAU.org. Retrieved 16 December 2017.
  17. ↑ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  18. ↑ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2008-10-25 at the Wayback Machine., Hong Kong Space Museum. Accessed on line November 23, 2010.
  19. ↑ Torres, Guillermo; Stefanik, Robert P.; Latham, David W. (1997). "The Hyades Binaries θ1 Tauri and θ2Tauri: The Distance to the Cluster and the Mass‐Luminosity Relation". The Astrophysical Journal. 485: 167. Bibcode:1997ApJ...485..167T. doi:10.1086/304422.
  20. ↑ Solano, E.; Fernley, J. (April 1997), "Spectroscopic survey of delta Scuti stars. I. Rotation velocities and effective temperatures", Astronomy & Astrophysics Supplement Series, 122: 131–147, Bibcode:1997A&AS..122..131S, doi:10.1051/aas:1997329.
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