fbpx
Wikipedia

Eta Draconis

January 06, 2023

Eta Draconis (η Draconis, abbreviated Eta Dra, η Dra) is a binary star in the northern circumpolar constellation of Draco. Despite having an apparent visual magnitude of only +2.73,[2] it is the second-brightest star in this generally faint constellation. Based upon parallax measurements collected during the Hipparcos mission, this star is located at a distance of about 92.1 light-years (28.2 parsecs) from the Sun.[1]

η Draconis
Location of η Draconis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Draco
Right ascension 16h 23m 59.48594s[1]
Declination +61° 30′ 51.1699″[1]
Apparent magnitude (V) +2.73[2]
Characteristics
Spectral type G8 III[2]
U−B color index +0.70[3]
B−V color index +0.91[3]
Astrometry
Radial velocity (Rv)–14.3[4] km/s
Proper motion (μ) RA: –17.02[1] mas/yr
Dec.: +56.95[1] mas/yr
Parallax (π)35.42 ± 0.09 mas[1]
Distance92.1 ± 0.2 ly
(28.23 ± 0.07 pc)
Absolute magnitude (MV)+0.58[5]
Details
Mass2.55[2] M☉
Radius11[6] R☉
Luminosity60[2] L☉
Surface gravity (log g)2.82[2] cgs
Temperature5,055[2] K
Metallicity [Fe/H]–0.04[2] dex
Rotational velocity (v sin i)8[7] km/s
Age550[2] Myr
Other designations
Aldibain, Athebyne, 14 Draconis, BD+61 1591, FK5 822, HD 148387, HIP 80331, HR 6132, NSV 7713, SAO 17074, WDS 16240+6131.[8]
Database references
SIMBADdata

The two components are designated Eta Draconis A (also named Athebyne /ˈæθɪbaɪn/[9]) and B.

Nomenclature

η Draconis (Latinised to Eta Draconis) is the system's Bayer designation. The designations of the two components as Eta Draconis A and B derives from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[10]

Eta Draconis, together with Zeta Draconis, bore the traditional Arabic name الذئبين al-dhiʼbayn, "the (two) wolves", lying in wait for the camel's foal, the little star Al Rubaʽ, protected by the Mother Camels.[11]

In 2016, the IAU organized a Working Group on Star Names (WGSN)[12] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[13] It approved the name Athebyne (a rendering of adh-dhiʼbayn) for the component Eta Draconis A on 5 September 2017. It approved the name Aldhibah (the female wolf) for Zeta Draconis A on the same date. Both are now so included in the List of IAU-approved Star Names.[9]

In Chinese, 紫微左垣 (Zǐ Wēi Zuǒ Yuán), meaning Left Wall of Purple Forbidden Enclosure, refers to an asterism consisting of Eta Draconis, Iota Draconis, Theta Draconis, Zeta Draconis, Upsilon Draconis, 73 Draconis, Gamma Cephei and 23 Cassiopeiae.[14] Consequently, the Chinese name for Eta Draconis itself is 紫微左垣三 (Zǐ Wēi Zuǒ Yuán sān, English: the Third Star of Left Wall of Purple Forbidden Enclosure),[15] representing 少宰 (Shàozǎi), meaning The Second Premier.[16] Possibly, 少宰 (Shàozǎi) is westernized into Hea Tsae by R.H. Allen with meaning "the Lowest Steward" but it was for Theta Draconis.[17]

Properties

Eta Draconis A is a star with 2.55[2] times the mass of the Sun. The spectrum matches a stellar classification of G8 III,[2] with the luminosity class III indicating this is an evolved giant star that has exhausted the supply of hydrogen at its core. It reached this stage in only 550[2] million years because higher mass stars such as this consume the supply of hydrogen more rapidly than the Sun. The measured angular diameter of this star, after correction for limb darkening, is 3.72 ± 0.07 mas.[18] At the estimated distance of Eta Draconis,[1] this yields a physical size of about 11 times the radius of the Sun.[6] From its extended envelope, it is radiating around 60 times the luminosity of the Sun at an effective temperature of 5,055 K,[2] giving it the yellow glow of a G-type star.[19]

Eta Draconis B is located at an angular separation of 5.1 arcseconds from the primary. This is an 8.8 magnitude K-type main sequence star with a stellar classification of K2 V.[20] At the estimated distance of this star system, the two stars are separated by a physical distance of at least 140 AU and require at least a millennium to complete an orbit.[21]

References

  1. ^ a b c d e f g van Leeuwen, F. (November 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
  2. ^ a b c d e f g h i j k l m Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke (August 2008), "Stellar parameters and elemental abundances of late-G giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv:0805.2434, Bibcode:2008PASJ...60..781T, doi:10.1093/pasj/60.4.781
  3. ^ a b Nicolet, B. (1978). "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System". Astronomy and Astrophysics Supplement Series. 34: 1–49. Bibcode:1978A&AS...34....1N.
  4. ^ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
  5. ^ Pizzolato, N.; Maggio, A.; Sciortino, S. (September 2000), "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases", Astronomy and Astrophysics, 361: 614–628, Bibcode:2000A&A...361..614P
  6. ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
     
  7. ^ Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago. 239 (1). Bibcode:1970CoAsi.239....1B.
  8. ^ "eta Dra". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-02-20.
  9. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
  10. ^ 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].
  11. ^ Star Name - R.H Allen p. 202
  12. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  13. ^ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  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.
  15. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 10 日
  16. ^ (in Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name August 10, 2010, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  17. ^ Star Name - R.H. Allen p. 210
  18. ^ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039
  19. ^ , 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
  20. ^ 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.
  21. ^ Kaler, James B., "AL DHIBAIN "PRIOR" (Eta Draconis)", Stars, University of Illinois, retrieved 2012-02-20


January 06, 2023
draconis, draconis, abbreviated, binary, star, northern, circumpolar, constellation, draco, despite, having, apparent, visual, magnitude, only, second, brightest, star, this, generally, faint, constellation, based, upon, parallax, measurements, collected, duri. Eta Draconis h Draconis abbreviated Eta Dra h Dra is a binary star in the northern circumpolar constellation of Draco Despite having an apparent visual magnitude of only 2 73 2 it is the second brightest star in this generally faint constellation Based upon parallax measurements collected during the Hipparcos mission this star is located at a distance of about 92 1 light years 28 2 parsecs from the Sun 1 h DraconisLocation of h Draconis circled Observation dataEpoch J2000 0 Equinox J2000 0Constellation DracoRight ascension 16h 23m 59 48594s 1 Declination 61 30 51 1699 1 Apparent magnitude V 2 73 2 CharacteristicsSpectral type G8 III 2 U B color index 0 70 3 B V color index 0 91 3 AstrometryRadial velocity Rv 14 3 4 km sProper motion m RA 17 02 1 mas yr Dec 56 95 1 mas yrParallax p 35 42 0 09 mas 1 Distance92 1 0 2 ly 28 23 0 07 pc Absolute magnitude MV 0 58 5 DetailsMass2 55 2 M Radius11 6 R Luminosity60 2 L Surface gravity log g 2 82 2 cgsTemperature5 055 2 KMetallicity Fe H 0 04 2 dexRotational velocity v sin i 8 7 km sAge550 2 MyrOther designationsAldibain Athebyne 14 Draconis BD 61 1591 FK5 822 HD 148387 HIP 80331 HR 6132 NSV 7713 SAO 17074 WDS 16240 6131 8 Database referencesSIMBADdataThe two components are designated Eta Draconis A also named Athebyne ˈ ae 8 ɪ b aɪ n 9 and B Nomenclature Edith Draconis Latinised to Eta Draconis is the system s Bayer designation The designations of the two components as Eta Draconis A and B derives from the convention used by the Washington Multiplicity Catalog WMC for multiple star systems and adopted by the International Astronomical Union IAU 10 Eta Draconis together with Zeta Draconis bore the traditional Arabic name الذئبين al dhiʼbayn the two wolves lying in wait for the camel s foal the little star Al Rubaʽ protected by the Mother Camels 11 In 2016 the IAU organized a Working Group on Star Names WGSN 12 to catalog and standardize proper names for stars The WGSN decided to attribute proper names to individual stars rather than entire multiple systems 13 It approved the name Athebyne a rendering of adh dhiʼbayn for the component Eta Draconis A on 5 September 2017 It approved the name Aldhibah the female wolf for Zeta Draconis A on the same date Both are now so included in the List of IAU approved Star Names 9 In Chinese 紫微左垣 Zǐ Wei Zuǒ Yuan meaning Left Wall of Purple Forbidden Enclosure refers to an asterism consisting of Eta Draconis Iota Draconis Theta Draconis Zeta Draconis Upsilon Draconis 73 Draconis Gamma Cephei and 23 Cassiopeiae 14 Consequently the Chinese name for Eta Draconis itself is 紫微左垣三 Zǐ Wei Zuǒ Yuan san English the Third Star of Left Wall of Purple Forbidden Enclosure 15 representing 少宰 Shaozǎi meaning The Second Premier 16 Possibly 少宰 Shaozǎi is westernized into Hea Tsae by R H Allen with meaning the Lowest Steward but it was for Theta Draconis 17 Properties EditEta Draconis A is a star with 2 55 2 times the mass of the Sun The spectrum matches a stellar classification of G8 III 2 with the luminosity class III indicating this is an evolved giant star that has exhausted the supply of hydrogen at its core It reached this stage in only 550 2 million years because higher mass stars such as this consume the supply of hydrogen more rapidly than the Sun The measured angular diameter of this star after correction for limb darkening is 3 72 0 07 mas 18 At the estimated distance of Eta Draconis 1 this yields a physical size of about 11 times the radius of the Sun 6 From its extended envelope it is radiating around 60 times the luminosity of the Sun at an effective temperature of 5 055 K 2 giving it the yellow glow of a G type star 19 Eta Draconis B is located at an angular separation of 5 1 arcseconds from the primary This is an 8 8 magnitude K type main sequence star with a stellar classification of K2 V 20 At the estimated distance of this star system the two stars are separated by a physical distance of at least 140 AU and require at least a millennium to complete an orbit 21 References Edit a b c d e f g van Leeuwen F November 2007 Validation of the new Hipparcos 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 a b c d e f g h i j k l m Takeda Yoichi Sato Bun ei Murata Daisuke August 2008 Stellar parameters and elemental abundances of late G giants Publications of the Astronomical Society of Japan 60 4 781 802 arXiv 0805 2434 Bibcode 2008PASJ 60 781T doi 10 1093 pasj 60 4 781 a b Nicolet B 1978 Photoelectric photometric Catalogue of homogeneous measurements in the UBV System Astronomy and Astrophysics Supplement Series 34 1 49 Bibcode 1978A amp AS 34 1N Wilson Ralph Elmer 1953 General Catalogue of Stellar Radial Velocities Washington Carnegie Institution of Washington Bibcode 1953GCRV C 0W Pizzolato N Maggio A Sciortino S September 2000 Evolution of X ray activity of 1 3 Msun late type stars in early post main sequence phases Astronomy and Astrophysics 361 614 628 Bibcode 2000A amp A 361 614P a b Lang Kenneth R 2006 Astrophysical formulae Astronomy and astrophysics library vol 1 3rd ed Birkhauser ISBN 3 540 29692 1 The radius R is given by 2 R 28 23 3 72 10 3 AU 0 0046491 AU R 22 6 R displaystyle begin aligned 2 cdot R amp frac 28 23 cdot 3 72 cdot 10 3 text AU 0 0046491 text AU R bigodot amp approx 22 6 cdot R bigodot end aligned Bernacca P L Perinotto M 1970 A catalogue of stellar rotational velocities Contributi Osservatorio Astronomico di Padova in Asiago 239 1 Bibcode 1970CoAsi 239 1B eta Dra SIMBAD Centre de donnees astronomiques de Strasbourg Retrieved 2012 02 20 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 Star Name R H Allen p 202 IAU 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 AEEA Activities of Exhibition and Education in Astronomy 天文教育資訊網 2006 年 6 月 10 日 in Chinese English Chinese Glossary of Chinese Star Regions Asterisms and Star Name Archived August 10 2010 at the Wayback Machine Hong Kong Space Museum Accessed on line November 23 2010 Star Name R H Allen p 210 Richichi A Percheron I Khristoforova M February 2005 CHARM2 An updated Catalog of High Angular Resolution Measurements Astronomy and Astrophysics 431 2 773 777 Bibcode 2005A amp A 431 773R doi 10 1051 0004 6361 20042039 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 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 Kaler James B AL DHIBAIN PRIOR Eta Draconis Stars University of Illinois retrieved 2012 02 20 Retrieved from https en wikipedia org w index php title Eta Draconis amp oldid 1099887571, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.