{{Short description|Star in the constellation Draco}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Draco constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=ω Draconis |x=366|y=609 }} | caption = Location of ω Draconis (circled in red) }} {{Starbox observe |constell=[[Draco (constellation)|Draco]] |epoch=[[J2000]] |ra={{RA|17|36|57.09431}}<ref name=dr3/> |dec={{DEC|+68|45|28.6815}}<ref name=dr3/> |appmag_v=4.80<ref name=UBV>{{cite journal|title=UBVRIJKL Photometry of the Bright Stars|author1=Johnson, H. L.|journal=Communications of the Lunar and Planetary Laboratory|volume=4|pages=99|date=1966|bibcode=1966CoLPL...4...99J}}</ref> }} {{Starbox character |type=[[main sequence]]<ref name=dr3/> |class=F5V<ref>{{cite journal|doi=10.1086/107457|title=Distribution of the nearer bright stars in the color-luminosity array|journal=The Astronomical Journal|volume=62|pages=45|year=1957|last1=Eggen|first1=O.|bibcode = 1957AJ.....62...45E |doi-access=free}}</ref> |b-v=+0.43<ref name=UBV/> |u-b=−0.01<ref name=UBV/> }} {{Starbox astrometry |radial_v={{val|-13.98|0.02}}<ref name=SB9>{{cite journal|title=S<sub>B<sup>9</sup></sub>: The ninth catalogue of spectroscopic binary orbits|display-authors=1|author1=Pourbaix, D.|author2=Tokovinin, A. A.|author3=Batten, A. H.|author4=Fekel, F. C.|author5=Hartkopf, W. I.|author6=Levato, H.|author7=Morrell, N. I.|author8=Torres, G.|author9=Udry, S.|journal=Astronomy and Astrophysics|volume=424|issue=2|pages=727–732|year=2004|doi=10.1051/0004-6361:20041213|arxiv=astro-ph/0406573|bibcode=2004A&A...424..727P|s2cid=119387088}}</ref> |prop_mo_ra=+1.690<ref name=dr3/> |prop_mo_dec=+321.452<ref name=dr3/> |parallax=42.0939 |p_error=0.1425 |parallax_footnote=<ref name=dr3>{{cite Gaia DR3|1637717179389828224}}</ref> |absmag_v=2.95<ref name=Anderson2012>{{citation | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | s2cid=119257644 | postscript=. }}</ref> }} {{Starbox orbit |reference=<ref name=Konacki/> |period_unitless={{val|5.2797766|0.0000044|u=d}} |axis_unitless={{val|3.469|0.017|ul=mas}} |inclination={{val|151.4|1.1}} |node={{val|1.23|0.32}} |eccentricity={{val|0.00220|0.00031}} |periarg={{val|314.8|5.6}} |periastron=[[Julian date|JD]] {{val|2454349.083|0.083}} |k1={{val|36.254|0.016}} |k2={{val|44.720|0.016}} }} {{Starbox detail |component1=ω Dra A |mass={{val|1.46|0.16}} |luminosity=5.61<ref name=Anderson2012/> |temperature=6,500 |metal_fe={{Val|0.18|0.05}}<ref name=Anderson2012/> |age_gyr=1.9<ref name=Anderson2012/> |component2=ω Dra B |mass2={{val|1.18|0.13}} |temperature2=5,900 |metal_fe2=0.0 }} {{Starbox catalog |names=ω Dra, [[Flamsteed designation|28]] Dra, [[Bonner Durchmusterung|BD]]+68°949, [[Gliese Catalogue of Nearby Stars|GJ]] 4017, [[Henry Draper Catalogue|HD]] 160922, [[Hipparcos catalogue|HIP]] 86201, [[Bright Star Catalog|HR]] 6596, [[Smithsonian Astrophysical Observatory Star Catalog|SAO]] 17576 }} {{Starbox reference |Simbad=*+ome+Dra }} {{Starbox end}} '''Omega Draconis''', [[Latinisation of names|Latinized]] from '''ω Draconis''' and also known as '''28 Draconis''', is a [[binary star]] in the [[constellation]] of [[Draco (constellation)|Draco]]. The system is fairly close, and is located about 78 [[light-year]]s (24 [[parsec]]s) away, based on its [[stellar parallax|parallax]].<ref name=dr3/>
Omega Draconis is a [[spectroscopic binary]], which means the two stellar components are too close to be [[angular resolution|resolved]] but periodic [[Doppler shift]]s in their [[spectrum|spectra]] indicate orbital motion. In this case, light from both stars can be detected, and it is a double-lined spectroscopic binary. The [[orbital period]] of the system is 5.28 days, and the [[orbital eccentricity|eccentricity]] of the system is 0.00220, implying a nearly circular [[orbit]]. The primary has a mass of {{solar mass|1.46|link=yes}}, and is an [[F-type main-sequence star]]. The secondary is less massive, at {{solar mass|1.18}}.<ref name=Konacki>{{cite journal | title=High-precision Orbital and Physical Parameters of Double-lined Spectroscopic Binary Stars—HD78418, HD123999, HD160922, HD200077, and HD210027 | last1=Konacki | first1=Maciej | last2=Muterspaugh | first2=Matthew W. | last3=Kulkarni | first3=Shrinivas R. | last4=Hełminiak | first4=Krzysztof G. | display-authors=1 | journal=The Astrophysical Journal | volume=719 | issue=2 | pages=1293–1314 | year=2010 | arxiv=0910.4482 | bibcode=2010ApJ...719.1293K | doi=10.1088/0004-637X/719/2/1293 | s2cid=119253596 }}</ref>
==Nomenclature== With [[27 Draconis]], it composed the Arabs' الأظفار الذئب ''al-ʼaẓfār al-dhiʼb'', "the hyena's claws" in the asterism of the [[Mother Camels]].<ref name="allen1899">{{citation | title=Star-Names and Their Meanings | last=Allen | first=Richard Hinckley | authorlink=Richard Hinckley Allen | date=1899 | publisher=G. E. Stechert | location=New York | page=212 }}</ref> The two stars have been distinguished as ''Adfar Aldib I'' (ω) and ''Adfar Aldib II'' (27 Draconis).<ref name=rhoads1971>{{citation | url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720005197_1972005197.pdf | first1=Jack W. | last1=Rhoads | title=Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars | publisher=Jet Propulsion Laboratory, California Institute of Technology | date=November 15, 1971 | postscript=. }}</ref>
In [[Chinese language|Chinese]], {{lang|zh|尚書}} ({{lang|zh-Latn|Shàng Shū}}), meaning ''[[Purple Forbidden enclosure|Royal Secretary]]'', refers to an asterism consisting of ω Draconis, [[15 Draconis]], [[18 Draconis]] and [[19 Draconis]].<ref name="ridpathdraco">[http://www.ianridpath.com/startales/draco.htm Ian Ridpath's Startales - Drco the Dragon]</ref> Consequently, ω Draconis itself is known as {{lang|zh|尚書一}} ({{lang|zh-Latn|Shàng Shū yī}}, {{langx|en|the First Star of Royal Secretary}}.).<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0606/ap060610.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 10 日] {{Webarchive|url=https://web.archive.org/web/20110521234349/http://aeea.nmns.edu.tw/2006/0606/ap060610.html |date=2011-05-21 }}</ref>
==References== {{Reflist}}
{{Stars of Draco}}
[[Category:Draco (constellation)]] [[Category:F-type main-sequence stars]] [[Category:Bayer objects|Draconis, Omega]] [[Category:Spectroscopic binaries]] [[Category:Hipparcos objects|086201]] [[Category:Flamsteed objects|Draconis, 28]] [[Category:Henry Draper Catalogue objects|160922]] [[Category:Bright Star Catalogue objects|6596]] [[Category:Durchmusterung objects|BD+68 0949]] [[Category:Gliese and GJ objects|4017]]