Gamma Draconis (γ Draconis, abbreviated Gamma Dra, γ Dra), formally named Eltanin/ɛlˈteɪnɪn/,[8][9] is a star in the northern constellation of Draco. Contrary to its gamma-designation (historically third-ranked), it is the brightest object in Draco at magnitude 2.2,[1] outshining Beta Draconis by nearly half a magnitude and Alpha Draconis by over a magnitude.
In 1.5 million years, Gamma Draconis will pass within 28 light-years of Earth. For a period, if its current absolute magnitude does not change, it will be the brightest star in the night sky, nearly as bright as Sirius is at present.[12][13] It is by far the brightest star having a zenith above a point near London which led to its vaunting in these places as the "zenith star".[14] From other locations it has a nearby bright, well-known star in Lyra in the night sky; finding Vega, Gamma Draconis is the red star just north-northwest of it.
Gamma Draconis is an evolvedgiant star with a stellar classification of K5 III.[3] Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[15] It has 72%[6] more mass than the Sun and it has expanded to around 48 times the Sun's girth.[5] It is radiating about 471[5] times as much luminosity as the Sun from its outer atmosphere at an effective temperature of 3,930 K.[5] This is cooler than the Sun, giving this star the orange-hued glow of a K-type star.[16]
Gamma Draconis has six companions listed in double star catalogues. All were discovered by the American astronomer Sherburne Wesley Burnham.[17] The closest may be physically associated and would be separated by about 1,000 AU. The luminosity of this object suggests it is a red dwarf star.[18] The others are all much more distant stars unrelated to Gamma Draconis.[19]
It bore the traditional name Eltanin[12][20] derived from the Arabic التنين At-Tinnin 'The great serpent'. The name Rastaban was formerly used for Gamma Draconis, and the two terms share an Arabic root meaning "serpent" or "dragon". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[21] to catalogue and standardize proper names for stars. The WGSN approved the name Eltanin for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.[9]
In Chinese, 天棓 (Tiān Bàng), meaning Celestial Flail, refers to an asterism consisting of Gamma Draconis, Xi Draconis, Nu Draconis, Beta Draconis and Iota Herculis.[22] Consequently, the Chinese name for Gamma Draconis itself is 天棓四 (Tiān Bàng sì, English: the Fourth Star of Celestial Flail.)[23]
^ abcdefgvan 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.
^ abcOja, T. (August 1991). "UBV photometry of stars whose positions are accurately known. VI". Astronomy and Astrophysics Supplement Series. 89 (2): 415–419. Bibcode:1991A&AS...89..415O.
^ abMorgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11 (1): 29, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333
^ abMassarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209
^ abcdefghPiau, L.; et al. (February 2011), "Surface convection and red-giant radius measurements", Astronomy and Astrophysics, 526: A100, arXiv:1010.3649, Bibcode:2011A&A...526A.100P, doi:10.1051/0004-6361/201014442, S2CID 118533297
^ abDehaes, S.; et al. (September 2011), "Structure of the outer layers of cool standard stars", Astronomy & Astrophysics, 533: A107, arXiv:0905.1240, Bibcode:2011A&A...533A.107D, doi:10.1051/0004-6361/200912442, S2CID 42053871
^McWilliam, Andrew (December 1990). "High-resolution spectroscopic survey of 671 GK giants". Astrophysical Journal Supplement Series (PDF). 74: 1075–1128. Bibcode:1990ApJS...74.1075M. doi:10.1086/191527.
^Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN978-1-931559-44-7.
^ ab"IAU Catalog of Star Names". Retrieved 28 July 2016.
^Perryman, M. A. C.; Lindegren, L.; Kovalevsky, J.; et al. (July 1997), "The Hipparcos Catalogue", Astronomy and Astrophysics, 323: L49–L52, Bibcode:1997A&A...323L..49P
^Perryman, Michael (2010), "The Making of History's Greatest Star Map", The Making of History's Greatest Star Map, Astronomers’ Universe, Heidelberg: Springer-Verlag, Bibcode:2010mhgs.book.....P, doi:10.1007/978-3-642-11602-5, ISBN978-3-642-11601-8
^ abcKaler, James B. "ELTANIN (Gamma Draconis)". Stars. University of Illinois. Retrieved 2010-11-21.
^Tomkin, Jocelyn (April 1998). "Once and Future Celestial Kings". Sky and Telescope. 95 (4): 59–63. Bibcode:1998S&T....95d..59T. – based on computations from HIPPARCOS data. (The calculations exclude stars whose distance or proper motion is uncertain.) PDF[permanent dead link]
^ abAllen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, p. 207, ISBN0-486-21079-0, retrieved 2010-12-12
^Garrison, R. F. (December 1993), , Bulletin of the American Astronomical Society, 25: 1319, Bibcode:1993AAS...183.1710G, archived from the original on 2019-06-25, retrieved 2012-02-04
^Mason, Brian D.; et al. (December 2001). . The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Archived from the original on 14 March 2016. Retrieved 13 March 2016.
^Ayres, Thomas R.; Brown, Alexander; Harper, Graham M. (November 2006), "The Coronae of γ Draconis", The Astrophysical Journal, 651 (2): 1126–1129, Bibcode:2006ApJ...651.1126A, doi:10.1086/507763, S2CID 120205574
^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.
^(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, ISBN978-986-7332-25-7.
^(in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 January 30, 2011, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
Notes
October 21, 2023
gamma, draconis, eltanin, etamin, redirect, here, other, uses, eltanin, disambiguation, etamin, disambiguation, draconis, abbreviated, gamma, formally, named, eltanin, star, northern, constellation, draco, contrary, gamma, designation, historically, third, ran. Eltanin and Etamin redirect here For other uses see Eltanin disambiguation and Etamin disambiguation Gamma Draconis g Draconis abbreviated Gamma Dra g Dra formally named Eltanin ɛ l ˈ t eɪ n ɪ n 8 9 is a star in the northern constellation of Draco Contrary to its gamma designation historically third ranked it is the brightest object in Draco at magnitude 2 2 1 outshining Beta Draconis by nearly half a magnitude and Alpha Draconis by over a magnitude Gamma DraconisLocation of g Draconis circled Observation dataEpoch J2000 Equinox J2000Constellation DracoRight ascension 17h 56m 36 36988s 1 Declination 51 29 20 0242 1 Apparent magnitude V 2 23 2 CharacteristicsSpectral type K5 III 3 U B color index 1 87 2 B V color index 1 53 2 AstrometryRadial velocity Rv 28 19 0 36 4 km sProper motion m RA 8 48 1 mas yr Dec 22 79 1 mas yrParallax p 21 14 0 10 mas 1 Distance154 3 0 7 ly 47 3 0 2 pc Absolute magnitude MV 1 93 0 07 5 DetailsMass1 72 6 M Radius48 15 1 09 5 R Luminosity471 30 5 L Surface gravity log g 1 55 5 cgsTemperature3 930 5 KMetallicity Fe H 0 14 7 dexRotational velocity v sin i 6 0 4 km sOther designationsEtamin citation needed Etanin citation needed Etanlin citation needed Ettanin citation needed Rastaban citation needed Rasaben citation needed Zenith star 33 Draconis BD 51 2282 FK5 676 HD 164058 HIP 87833 HR 6705 SAO 30653Database referencesSIMBADdataGamma Draconis is at a distance of 154 3 light years 47 3 parsecs from the Sun 1 as determined by parallax measurements from the Hipparcos astrometry satellite 10 11 In 1728 while unsuccessfully attempting to measure the parallax of this star the English astronomer James Bradley discovered the aberration of light resulting from the relative movement of the Earth Bradley s discovery apparently confirmed Copernicus theory that the Earth revolved around the Sun 12 It is drifting closer to the Solar System with a radial velocity of about 28 km s In 1 5 million years Gamma Draconis will pass within 28 light years of Earth For a period if its current absolute magnitude does not change it will be the brightest star in the night sky nearly as bright as Sirius is at present 12 13 It is by far the brightest star having a zenith above a point near London which led to its vaunting in these places as the zenith star 14 From other locations it has a nearby bright well known star in Lyra in the night sky finding Vega Gamma Draconis is the red star just north northwest of it Contents 1 Properties 2 Nomenclature 2 1 Namesake 3 See also 4 Notes and referencesProperties EditGamma Draconis is an evolved giant star with a stellar classification of K5 III 3 Since 1943 the spectrum of this star has served as one of the stable anchor points by which other stars are classified 15 It has 72 6 more mass than the Sun and it has expanded to around 48 times the Sun s girth 5 It is radiating about 471 5 times as much luminosity as the Sun from its outer atmosphere at an effective temperature of 3 930 K 5 This is cooler than the Sun giving this star the orange hued glow of a K type star 16 Gamma Draconis has six companions listed in double star catalogues All were discovered by the American astronomer Sherburne Wesley Burnham 17 The closest may be physically associated and would be separated by about 1 000 AU The luminosity of this object suggests it is a red dwarf star 18 The others are all much more distant stars unrelated to Gamma Draconis 19 Nomenclature Editg Draconis Latinised to Gamma Draconis is the star s Bayer designation It bore the traditional name Eltanin 12 20 derived from the Arabic التنين At Tinnin The great serpent The name Rastaban was formerly used for Gamma Draconis and the two terms share an Arabic root meaning serpent or dragon In 2016 the International Astronomical Union organized a Working Group on Star Names WGSN 21 to catalogue and standardize proper names for stars The WGSN approved the name Eltanin for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names 9 Gamma Draconis along with Beta Draconis Mu Draconis Nu Draconis and Xi Draconis were Al ʽAwaid the Mother Camels which was later known as the Quinque Dromedarii 14 In Chinese 天棓 Tian Bang meaning Celestial Flail refers to an asterism consisting of Gamma Draconis Xi Draconis Nu Draconis Beta Draconis and Iota Herculis 22 Consequently the Chinese name for Gamma Draconis itself is 天棓四 Tian Bang si English the Fourth Star of Celestial Flail 23 Namesake Edit USS Etamin was a United States Navy Crater class cargo ship named after the star See also EditList of stars in DracoNotes and references EditReferences a b c d e f g van Leeuwen F November 2007 Hipparcos the New Reduction Astronomy and Astrophysics 474 2 653 664 arXiv 0708 1752 Bibcode 2007A amp A 474 653V doi 10 1051 0004 6361 20078357 S2CID 18759600 Retrieved 2010 11 21 a b c Oja T August 1991 UBV photometry of stars whose positions are accurately known VI Astronomy and Astrophysics Supplement Series 89 2 415 419 Bibcode 1991A amp AS 89 415O a b Morgan W W Keenan P C 1973 Spectral Classification Annual Review of Astronomy and Astrophysics 11 1 29 Bibcode 1973ARA amp A 11 29M doi 10 1146 annurev aa 11 090173 000333 a b Massarotti Alessandro et al January 2008 Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity The Astronomical Journal 135 1 209 231 Bibcode 2008AJ 135 209M doi 10 1088 0004 6256 135 1 209 a b c d e f g h Piau L et al February 2011 Surface convection and red giant radius measurements Astronomy and Astrophysics 526 A100 arXiv 1010 3649 Bibcode 2011A amp A 526A 100P doi 10 1051 0004 6361 201014442 S2CID 118533297 a b Dehaes S et al September 2011 Structure of the outer layers of cool standard stars Astronomy amp Astrophysics 533 A107 arXiv 0905 1240 Bibcode 2011A amp A 533A 107D doi 10 1051 0004 6361 200912442 S2CID 42053871 McWilliam Andrew December 1990 High resolution spectroscopic survey of 671 GK giants Astrophysical Journal Supplement Series PDF 74 1075 1128 Bibcode 1990ApJS 74 1075M doi 10 1086 191527 Kunitzsch Paul Smart Tim 2006 A Dictionary of Modern star Names A Short Guide to 254 Star Names and Their Derivations 2nd rev ed Cambridge Massachusetts Sky Pub ISBN 978 1 931559 44 7 a b IAU Catalog of Star Names Retrieved 28 July 2016 Perryman M A C Lindegren L Kovalevsky J et al July 1997 The Hipparcos Catalogue Astronomy and Astrophysics 323 L49 L52 Bibcode 1997A amp A 323L 49P Perryman Michael 2010 The Making of History s Greatest Star Map The Making of History s Greatest Star Map Astronomers Universe Heidelberg Springer Verlag Bibcode 2010mhgs book P doi 10 1007 978 3 642 11602 5 ISBN 978 3 642 11601 8 a b c Kaler James B ELTANIN Gamma Draconis Stars University of Illinois Retrieved 2010 11 21 Tomkin Jocelyn April 1998 Once and Future Celestial Kings Sky and Telescope 95 4 59 63 Bibcode 1998S amp T 95d 59T based on computations from HIPPARCOS data The calculations exclude stars whose distance or proper motion is uncertain PDF permanent dead link a b Allen R H 1963 Star Names Their Lore and Meaning Reprint ed New York NY Dover Publications Inc p 207 ISBN 0 486 21079 0 retrieved 2010 12 12 Garrison R F December 1993 Anchor Points for the MK System of Spectral Classification Bulletin of the American Astronomical Society 25 1319 Bibcode 1993AAS 183 1710G archived from the original on 2019 06 25 retrieved 2012 02 04 The Colour of Stars Australia Telescope Outreach and Education Commonwealth Scientific and Industrial Research Organisation December 21 2004 archived from the original on 2012 03 18 retrieved 2012 01 16 Mason Brian D et al December 2001 The 2001 US Naval Observatory Double Star CD ROM I The Washington Double Star Catalog The Astronomical Journal 122 6 3466 3471 Bibcode 2001AJ 122 3466M doi 10 1086 323920 Archived from the original on 14 March 2016 Retrieved 13 March 2016 Ayres Thomas R Brown Alexander Harper Graham M November 2006 The Coronae of g Draconis The Astrophysical Journal 651 2 1126 1129 Bibcode 2006ApJ 651 1126A doi 10 1086 507763 S2CID 120205574 Brown A G A et al Gaia collaboration August 2018 Gaia Data Release 2 Summary of the contents and survey properties Astronomy amp Astrophysics 616 A1 arXiv 1804 09365 Bibcode 2018A amp A 616A 1G doi 10 1051 0004 6361 201833051 g Dra Eltanin Wikisky org Retrieved 2010 11 22 IAU Working Group on Star Names WGSN International Astronomical Union retrieved 22 May 2016 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 January 30 2011 at the Wayback Machine Hong Kong Space Museum Accessed on line November 23 2010 Notes Retrieved from https en wikipedia org w index php title Gamma Draconis amp oldid 1176947170, wikipedia, wiki, book, books, library,
