Delta¹ Tauri (
Observation data Epoch J2000.0 Equinox J2000.0 (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] |
Astrometry | |
Proper motion ( | RA: +106.56[1] mas/yr Dec.: −29.18[1] mas/yr |
Parallax ( | 20.96 ± 0.58 mas[1] |
Distance | 156 ± 4 ly (48 ± 1 pc) |
Absolute magnitude (MV) | +0.41[5] |
Orbit[6] | |
Period (P) | 529.8 d |
Eccentricity (e) | 0.42 |
Periastron epoch (T) | 2434356.5 JD |
Argument of periastron ( (secondary) | 335° |
Semi-amplitude (K1) (primary) | 3.0 km/s |
Details[7] | |
Mass | 2.8±0.5 M☉ |
Radius | 11.4 R☉ |
Luminosity | 69 L☉ |
Temperature | 5,000 K |
Metallicity [Fe/H] | +0.10 dex |
Rotation | 138.2 d |
Rotational velocity (v sin i) | 4.2 km/s |
Age | 620[8] Myr |
Mass | 1.28±0.1 M☉ |
Other designations | |
Database references | |
SIMBAD | data |
The two constituents are designated
Nomenclature
editThe system bore the traditional name Hyadum II, which is Latin for "Second of the Hyades".[12] In 2016, the I
In Chinese, 畢宿 (Bì Xiù), meaning Net, refers to an asterism consisting of
Properties
editDelta¹ 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
edit- ^ a b c d e f van Leeuwen, F. (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, S2CID 18759600.
- ^ a b c d Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants", Monthly Notices of the Royal Astronomical Society, 172 (3): 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
- ^ a b Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
- ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- ^ Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics, 430 (1): 303–311, arXiv:astro-ph/0409683, Bibcode:2005A&A...430..303C, doi:10.1051/0004-6361:20041440, S2CID 12136256.
- ^ a b Pourbaix, D.; et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", Astronomy & Astrophysics, 424 (2): 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
- ^ a b c d Beck, P. G.; et al. (January 2015), "Detection of solar-like oscillations in the bright red giant stars
γ Psc andθ 1 Tau from a 190-day high-precision spectroscopic multisite campaign", Astronomy & Astrophysics, 573: 15, arXiv:1407.6352, Bibcode:2015A&A...573A.138B, doi:10.1051/0004-6361/201323019, S2CID 33898282, A138. - ^ Jofré, E.; et al. (2015), "Stellar parameters and chemical abundances of 223 evolved stars with and without planets", Astronomy & Astrophysics, 574: A50, arXiv:1410.6422, Bibcode:2015A&A...574A..50J, doi:10.1051/0004-6361/201424474, S2CID 53666931.
- ^ "del01 Tau". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-08.
{{cite web}}
: CS1 maint: postscript (link) - ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
- ^ 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].
- ^ Kaler, James B., "Hyadum II", STARS, University of Illinois, retrieved 2017-08-09.
- ^ "I
AU Working Group on Star Names (WGSN)". Retrieved 22 May 2016. - ^ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
- ^ (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. - ^ (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. - ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.