Delta1 Tauri

Source: Wikipedia, the free encyclopedia.
For other stars with this Bayer designation, see δ Tauri.
Delta¹ Tauri
Location of δ¹ Tauri (circled)
Observation data
ICRS
)
Constellation Taurus
Right ascension 04h 22m 56.09253s[1]
Declination +17° 32′ 33.0487″[1]
Apparent magnitude (V) +3.772[2] (3.90 + 9.50)[3]
Characteristics
Spectral type G9.5 III CN0.5[4]
U−B color index +0.801[2]
B−V color index +0.919[2]
Distance
156 ± 4 ly
(48 ± 1 pc)
Absolute magnitude (MV)+0.41[5]
Semi-amplitude
(K1)
(primary)		3.0 km/s
Details
Myr
δ¹ Tau Ab
Mass1.28±0.1 M☉
HR 1373, SAO 93897[9]
Database references
SIMBADdata

Delta¹ Tauri (δ¹ Tauri, abbreviated Delta¹ Tau, δ¹ Tau) is a double star in the zodiac constellation of Taurus. Based upon an annual parallax shift of 20.96 mas as seen from Earth,[1] it is located roughly 156 light-years distant from the Sun. The system is faintly visible to the naked eye with a combined apparent visual magnitude of +3.772.[2] It is considered a member of the Hyades cluster.[7]

The two constituents are designated δ¹ Tauri A and B. A is itself a binary star with components designated δ¹ Tauri Aa (officially named Secunda Hyadum /sɪˈkʌndə ˈhaɪədəm/, the traditional name for the entire system)[10] and Ab.

Nomenclature

δ¹ Tauri (Latinised to Delta¹ Tauri) is the system's Bayer designation. The designations of the two constituents as Delta¹ Tauri A and B, and those of A's components - Delta¹ Tauri Aa and Ab - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[11]

The system bore the traditional name Hyadum II, which is

multiple systems.[14] It approved the name Secunda Hyadum for the component Delta¹ Tauri Aa on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.[10]

In

Chinese name for Delta¹ Tauri itself is 畢宿三 (Bì Xiù sān), "the Third Star of Net".[16]

Properties

Delta¹ Tauri A is a single-lined spectroscopic binary with an orbital period of 529.8 days and an eccentricity of 0.42.[6] The visible member, component Aa, is an evolved G- or K-type giant star with a stellar classification of G9.5 III CN0.5.[4] The 'CN0.5' suffix indicates a mild overabundance of cyanogen in the outer atmosphere. It is chromospherically active and shows a radial velocity variation of 9.3±0.2 m/s with a period of 165±3 d.[7] The primary, component Aa, has 2.8 times the mass of the Sun, while the secondary, component Ab, has 1.3 times the Sun's mass.[7]

Delta¹ Tauri B is a magnitude 13.21 visual companion separated by 111.8 arcseconds from A.[3] It is most likely not physically related to the main star.[17]

References

  1. ^
    S2CID 18759600
    .
  2. ^
    doi:10.1093/mnras/172.3.667
    .
  3. ^
    doi:10.1086/323920
    .
  4. ^
    doi:10.1086/191373
    .
  5. S2CID 12136256
    .
  6. ^
    S2CID 119387088
    .
  7. ^
    S2CID 33898282
    , A138.
  8. S2CID 53666931
    .
  9. ^ "del01 Tau". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-08.{{cite web}}: CS1 maint: postscript (link)
  10. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
  11. arXiv:1012.0707 [astro-ph.SR
    ].
  12. University of Illinois
    , retrieved 2017-08-09.
  13. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  14. ^ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  15. ISBN 978-986-7332-25-7
    .
  16. ^ (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.
  17. S2CID 14878976
    .
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