Theta Tauri

θ Tauri

Hyades showing θ Tauri
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Taurus
θ1 Tauri
Right ascension 04h 28m 34.49209s
Declination +15° 57′ 44.2832″
Apparent magnitude (V) +3.84
θ2 Tauri
Right ascension 04h 28m 39.74455s
Declination +15° 52′ 15.1226″
Apparent magnitude (V) +3.35 - 3.42
Characteristics
θ1 Tauri
Spectral type G9 III Fe-0.5
θ2 Tauri
Spectral type A7 III
Variable type δ Scuti
Astrometry
θ1 Tauri
Parallax (π)21.4183±0.3731 mas
Distance152 ± 3 ly
(46.7 ± 0.8 pc)
Absolute magnitude (MV)+0.416
θ2 Tauri
Parallax (π)20.8354±0.3731 mas
Distance157 ± 3 ly
(48.0 ± 0.9 pc)
Absolute magnitude (MV)+0.08
Orbit
PrimaryA
SecondaryB
Period (P)5,997 days
Eccentricity (e)0.64
Semi-amplitude (K1)
(primary)		8.39 km/s
Orbit
PrimaryAa
SecondaryAb
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
Aa
Mass2.86 M☉
Radius4.4 R☉
Luminosity59 L☉
Surface gravity (log g)3.6 cgs
Temperature7,800 K
Rotational velocity (v sin i)68.4 km/s
Ab
Mass2.16 M☉
Radius2.7 R☉
Luminosity21 L☉
Temperature7,800 K
Rotational velocity (v sin i)113 km/s
Age650 Myr
θ1 Tauri
Mass2.67 M☉
Radius9.42±0.22 R☉
Luminosity47.7±2.3 L☉
Surface gravity (log g)3.21 cgs
Temperature4,940±55 K
Metallicity [Fe/H]+0.14 dex
Rotational velocity (v sin i)1.40 km/s
Age510 Myr
Other designations
θ Tauri
θ1 Tauri: 77 Tauri, BD+15 631, HD 28307, HIP 20885, HR 1411, SAO 93955
θ2 Tauri: Chamukuy, 78 Tauri, BD+15 632, HD 28319, HIP 20894, HR 1412, SAO 93957
Database references
SIMBADθ1 Tauri
θ2 Tauri

Theta Tauri (θ Tauri, abbreviated Theta 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 (Theta Tauri B) and Theta2 Tauri (Theta Tauri A). Theta² is brighter, hence the pair are sometimes referred to as Theta Tauri B and A, 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 (formally named Chamukuy /ˈtʃɑːmuːkuːi/), Ab, Ba, and Bb.

Nomenclature

The θ Tauri pair, showing contrasting blue and yellow colors, in the Hyades cluster. In this image, θ1 Tauri is above in yellow, and θ2 Tauri is below in light blue.

θ Tauri (Latinised to Theta Tauri) is the double star's Bayer designation;[citation needed] 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).

In the mythology of the Maya peoples, Theta Tauri is known as Chamukuy, meaning a small bird in the Yucatec Maya language. In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. 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.

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. Consequently, the Chinese name for Theta² Tauri itself is 畢宿六 (Bì Xiù liù), "the Sixth Star of Net".

Properties

A light curve for Theta2 Tauri, plotted from TESS data

Theta Tauri A 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. Its primary component, Theta Tauri Aa, is a white A-type giant. The secondary, Theta Tauri Ab, is of the 6th magnitude and is 0.005 arcseconds, or at least 2 AU, distant. It completes an orbit once every 141 days.

Theta Tauri B is the dimmer constituent. Its primary component, Theta Tauri Ba, is an orange K-type giant with an apparent magnitude of +3.84. The secondary, Theta Tauri Bb, 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.

References

  1. 1 2 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.
  2. 1 2 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.
  3. 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.
  4. ↑ Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins Catalog of Revised MK Types for the Cooler Stars". The Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
  5. ↑ Morgan, W. W.; Abt, Helmut A.; Tapscott, J. W. (1978). Revised MK Spectral Atlas for stars earlier than the sun. Bibcode:1978rmsa.book.....M.
  6. ↑ 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.
  7. ↑ 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.
  8. ↑ Mermilliod, J. -C; Andersen, J.; Latham, D. W.; Mayor, M. (2007). "Red giants in open clusters. XIII. Orbital elements of 156 spectroscopic binaries". Astronomy and Astrophysics. 473 (3): 829. Bibcode:2007A&A...473..829M. doi:10.1051/0004-6361:20078007.
  9. 1 2 3 4 5 6 7 Torres, K. B. V.; Lampens, P.; Frémat, Y.; Hensberge, H.; Lebreton, Y.; Škoda, P.; Guenther, E.; Schwope, A.; Heber, U. (2011). "Spectra disentangling applied to the Hyades binary θ2 Tauri AB: New orbit, orbital parallax and component properties". Astronomy and Astrophysics. 525: A50. arXiv:1010.5643. Bibcode:2011A&A...525A..50T. doi:10.1051/0004-6361/201015166. S2CID 55408682.
  10. 1 2 3 4 5 6 Liakos, Alexios; Niarchos, Panagiotis (2017). "Catalogue and properties of δ Scuti stars in binaries". Monthly Notices of the Royal Astronomical Society. 465 (1): 1181. arXiv:1611.00200. Bibcode:2017MNRAS.465.1181L. doi:10.1093/mnras/stw2756.
  11. 1 2 3 4 5 Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; de la Villarmois, E. Artur; Chavero, C.; Gómez, M.; Mauas, P. J. D.; Heber, U. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy and Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. S2CID 53666931.
  12. 1 2 3 Baines, Ellyn K.; Thomas Armstrong, J.; Clark, James H.; Gorney, Jim; Hutter, Donald J.; Jorgensen, Anders M.; Kyte, Casey; Mozurkewich, David; Nisley, Ishara; Sanborn, Jason; Schmitt, Henrique R.; Van Belle, Gerard T. (2021). "Angular Diameters and Fundamental Parameters of Forty-four Stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 162 (5): 198. arXiv:2211.09030. Bibcode:2021AJ....162..198B. doi:10.3847/1538-3881/ac2431.
  13. ↑ 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].
  14. ↑ Susan Milbrath (1 January 2010). Star Gods of the Maya: Astronomy in Art, Folklore, and Calendars. University of Texas Press. ISBN 978-0-292-77851-1.
  15. ↑ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  16. ↑ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  17. ↑ "Naming Stars". IAU.org. Retrieved 16 December 2017.
  18. ↑ 陳久金 (2005). 中國星座神話. 五南圖書出版股份有限公司. ISBN 978-986-7332-25-7.
  19. ↑ (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.
  20. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  21. ↑ 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.
  22. ↑ 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 (1): 167. Bibcode:1997ApJ...485..167T. doi:10.1086/304422.