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
Absolute magnitude (V)+0.416[2]
Distance154 ± 2[1] ly
(47.3 ± 0.6 pc)
Spectral typeK0 IIIb Fe-0.5
Other designations
77 Tau, BD+15 631, HD 28307, HIP 20885, HR 1411, SAO 93955.
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) +3.40
Distance150 ± 3[1] ly
(46.1 ± 1.0 pc)
Spectral typeA7 III
Other designations
Phaesula, 78 Tau, BD+15 632, HD 28319, HIP 20894, HR 1412, SAO 93957.

Theta Tauri (θ Tau, θ Tauri) is a double star in the constellation Taurus and a member of the Hyades open cluster. It dominated by two 3rd magnitude stars, θ1 Tauri and θ2 Tauri, which are separated by 5.62 arcminutes (0.094°) on the sky. Based upon parallax measurements, the first component, θ1 Tauri, is located at a distance of 154.4 ly (47.3 pc), while the second component, θ2 Tauri is at a distance of 150.4 light-years (46.1 parsecs).[1] If these estimates are correct, then the two components are separated by about four light years and hence are unlikely to form a binary star system.

θ1 Tauri is the dimmer star, an orange K-type giant with an apparent magnitude of +3.84. θ2 Tauri is a white A-type giant with a mean apparent magnitude of +3.40. θ2 Tauri 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.[3]

Both bright stars are spectroscopic binaries and have at least one closer companion. θ1 Tauri has a 7th-magnitude companion. It has a mass of 1.31 M☉ and orbits the primary every 16.26 years on a fairly eccentric (at 0.570) orbit.[4] θ2 has a 6th magnitude companion 0.005 arcseconds, or at least 2 AU, distant. It completes an orbit once every 141 days.

Culture signification

The Yucatec Maya say that this star is chakumuy, the name of small bird.[5]

References

  1. 1 2 3 4 5 6 7 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752 Freely accessible, doi:10.1051/0004-6361:20078357
  2. ↑ 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.
  3. ↑ Solano, E.; Fernley, J. (April 1997), "Spectroscopic survey of delta Scuti stars. I. Rotation velocities and effective temperatures", A & A Supplement series, 122: 131−147, Bibcode:1997A&AS..122..131S, doi:10.1051/aas:1997329.
  4. ↑ 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.
  5. ↑ p. 253, Star gods of the Maya: astronomy in art, folklore, and calendars, Susan Milbrath, Texas, University of Texas, 1999.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.