Delta1 Tauri

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Template:Other stars by Bayer designation

δ1 Tauri
Template:Location mark
Location of δ1 Tauri (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Taurus
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) +3.772[2] (3.90 + 9.50)[3]
Characteristics
Evolutionary stage red clump[4]
Spectral type G9.5 III CN0.5[5]
U−B Template:Engvar +0.801[2]
B−V Template:Engvar +0.919[2]
Astrometry
Proper motion (μ) RA: +106.56[1] mas/yr
Dec.: −29.18[1] mas/yr
Parallax (π)20.96±0.58 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)+0.41[6]
Orbit[7]
Period (P)529.8 d
Eccentricity (e)0.42
Periastron epoch (T)2434356.5 JD
Argument of periastron (ω)
(secondary)		335°
Semi-amplitude (K1)
(primary)		3.0 km/s
Details
δ1 Tau Aa
Mass2.75[4] Template:Solar mass
Radius14.9[4] Template:Solar radius
Luminosity107[4] Template:Solar luminosity
Surface gravity (log g)2.72[8] cgs
Temperature4,819[4] K
Metallicity [Fe/H]+0.11[8] dex
Rotation148.2 d[4]
Rotational velocity (v sin i)2.31[9] km/s
Age588[4] Myr
δ1 Tau Ab
MassTemplate:Val Template:Solar mass
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[10]
Database references
SIMBADdata

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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.[4]

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 Template:IPAc-en, the traditional name for the entire system)[11] 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).[12]

The system bore the traditional name Hyadum II, which is Latin for "Second of the Hyades".[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 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.[11]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Net, refers to an asterism consisting of δ1 Tauri, Epsilon Tauri, Delta³ Tauri, Gamma Tauri, Alpha Tauri (Aldebaran), 71 Tauri and Lambda Tauri.[16] Consequently, the Chinese name for Delta1 Tauri itself is Script error: No such module "Lang". (Script error: No such module "Lang".), "the Third Star of Net".[17]

Properties

Delta1 Tauri A is a single-lined spectroscopic binary with an orbital period of 529.8 days and an eccentricity of 0.42.[7] The visible member, component Aa, is an evolved G- or K-type giant star with a stellar classification of G9.5 III CN0.5.[5] 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 Template:Val with a period of Template:Val. The primary, component Aa, has 2.75 times the mass of the Sun, while the secondary, component Ab, has 1.3 times the Sun's mass. The primary star, at an age of 588 million years, is just evolving away from the horizontal branch toward the asymptotic giant branch after exhausting its core helium.[4]

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.[18]

References

Template:Reflist

Template:Stars of Taurus

Template:Authority control

  1. ↑ a b c d e f Cite error: Invalid <ref> tag; no text was provided for refs named vanLeeuwen2007
  2. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named Jennens1975
  3. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named WDSC2014
  4. ↑ a b c d e f g h i Cite error: Invalid <ref> tag; no text was provided for refs named schroder2020
  5. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named perkins1989
  6. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Cardini2005
  7. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named Pourbaix2004
  8. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named rp2024
  9. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named jofre2015
  10. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named SIMBAD
  11. ↑ a b Script error: No such module "citation/CS1".
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Kaler
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN.
  17. ↑ Template:In lang 香港太空館 - 研究資源 - 亮星中英對照表 Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010.
  18. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Eggleton2008
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