Binary star system in the constellation Draco
Theta Draconis , a name Latinized from θ Draconis, is a binary star system in the northern circumpolar constellation of Draco . It is faintly visible to the naked eye at night with an apparent visual magnitude of 4.12.[ 1] Parallax measurements place it at an estimated distance of 68.6 light-years (21.0 parsecs ) from the Sun ,[ 1] radial velocity of −8 km/s.[ 6] proper motion , traversing the celestial sphere at the rate of [ 12] O. J. Eggen included this star as a member of the NGC 1901 supercluster based on its space motion.[ 13]
The binary nature of this system was discovered by W. W. Campbell in 1899, and the first set of orbital elements was published by H. D. Curtis in 1907.[ 14] spectroscopic binary in a close orbit with a period of 3.07 days and an eccentricity (ovalness) of 0.04.[ 2] infrared H band , allowing an estimation of the mass ratio as ± 0.03[ 8] K1 was observed by M. Mayor and T. Mazeh in 1987, which is suggestive of a tertiary component to the system.[ 15]
The primary component is a solar-type star [ 4] stellar classifications of F9 V[ 2] [ 3] projected rotational velocity of 31 km/s.[ 7] metallicity (heavy element abundances) with around 20%[ 8] [ 10] chromospheric emission and may be on or entering the subgiant stage . Because of the close orbit, it could be filling up to 60% of its Roche lobe .[ 16] photosphere at an effective temperature of [ 10]
Chinese name
In Chinese , 紫微左垣 Zǐ Wēi Zuǒ Yuán Left Wall of Purple Forbidden Enclosure ι Draconis , η Draconis , ζ Draconis , υ Draconis , 73 Draconis , γ Cephei and 23 Cassiopeiae .[ 17] Chinese name for θ Draconis itself is 紫微左垣二 Zǐ Wēi Zuǒ Yuán èr the Second Star of Left Wall of Purple Forbidden Enclosure .),[ 18] 上宰 Shǎngzǎi The First Premier .[ 19] Shang Tsae by R.H. Allen with meaning "the Minor Steward" but it was for η Dra (Aldibain).[ 20]
References
^ a b c d e f g h van Leeuwen, F. (November 2007). "Hipparcos, the New Reduction" . Astronomy and Astrophysics . 474 (2): 653– 664. arXiv :0708.1752 Bibcode :2007A&A...474..653V . doi :10.1051/0004-6361:20078357 . S2CID 18759600 . Retrieved 2010-11-21 . ^ a b c Abt, Helmut A. (2009). "MK Classifications of Spectroscopic Binaries". The Astrophysical Journal Supplement . 180 (1): 117– 18. Bibcode :2009ApJS..180..117A . doi :10.1088/0067-0049/180/1/117 . S2CID 122811461 . ^ a b c d Tokovinin, A.; et al. (May 2006). "Tertiary companions to close spectroscopic binaries". Astronomy and Astrophysics . 450 (2): 6811– 693. arXiv :astro-ph/0601518 Bibcode :2006A&A...450..681T . doi :10.1051/0004-6361:20054427 . S2CID 8899546 . ^ a b Mazeh, Tsevi; et al. (December 1992). "On the Mass-Ratio Distribution of Spectroscopic Binaries with Solar-Type Primaries". Astrophysical Journal . 401 : 265. Bibcode :1992ApJ...401..265M . doi :10.1086/172058 . ^ Mermilliod, J. -C (1986). "Compilation of Eggen's UBV data, transformed to UBV (Unpublished)". Catalogue of Eggen's UBV Data . Bibcode :1986EgUBV........0M . ^ a b c 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 . S2CID 119257644 . ^ a b c d Luck, R. Earle (January 2017). "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants" . The Astronomical Journal . 153 (1): 19. arXiv :1611.02897 Bibcode :2017AJ....153...21L . doi :10.3847/1538-3881/153/1/21 S2CID 119511744 . 21. ^ a b c d e Mazeh, Tsevi; et al. (January 2002). "Infrared Detection of Low-Mass Secondaries in Spectroscopic Binaries". The Astrophysical Journal . 564 (2): 1007– 1014. arXiv :astro-ph/0110536 Bibcode :2002ApJ...564.1007M . doi :10.1086/324404 . S2CID 12431948 . ^ Heacox, William D. (December 1999). "On the Nature of Low-Mass Companions to Solar-like Stars" . The Astrophysical Journal . 526 (2): 928– 936. Bibcode :1999ApJ...526..928H . doi :10.1086/308033 ^ a b c d e 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 .^ "tet Dra" . SIMBAD Centre de données astronomiques de Strasbourg . Retrieved 2021-01-10 .^ Lépine, Sébastien; Shara, Michael M. (March 2005). "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)". The Astronomical Journal . 129 (3): 1483– 1522. arXiv :astro-ph/0412070 Bibcode :2005AJ....129.1483L . doi :10.1086/427854 . S2CID 2603568 . ^ Eggen, Olin J. (1996). "The Stellar Content of Star Stream I". Astronomical Journal . 111 : 1615. Bibcode :1996AJ....111.1615E . doi :10.1086/117901 . ^ Curtis, H. D. (November 1907). "Orbit of the spectroscopic binary theta Draconis" . Astrophysical Journal . 26 : 263−267. Bibcode :1907ApJ....26..263C . doi :10.1086/141500 S2CID 222445276 . ^ Mayor, M.; Mazeh, T. (January 1987). "The frequency of triple and multiple stellar systems". Astronomy and Astrophysics . 171 : 157– 177. Bibcode :1987A&A...171..157M . ^ Young, A.; Koniges, A. (February 1977). "A study of the occurrence of singly ionized calcium emission in late-type spectroscopic binary stars" . Astrophysical Journal . 211 : 836– 843. Bibcode :1977ApJ...211..836Y . doi :10.1086/154992 ^ (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) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 10 日 Archived 2011-05-21 at the Wayback Machine ^ (in Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Archived 2008-09-24 at the Wayback Machine , Hong Kong Space Museum. Accessed on line November 23, 2010.^ Allen, R. H. (1963). "Draco, the Dragon" . Star Names, their Lore and Meaning (Dover ed.). p. 210. Retrieved 2021-01-11 .
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