{{Short description|Binary star system 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=6 Draconis |x=876|y=396 }} | caption = Location of 6 Draconis (circled in red) }} {{Starbox observe | epoch = J2000 | constell = [[Draco (constellation)|Draco]] | ra = {{RA|12|34|44.01929}}<ref name=GaiaDR3/> | dec = {{DEC|+70|01|18.4053}}<ref name=GaiaDR3/> | appmag_v = 4.95<ref name=Anderson2012/> }} {{Starbox character | type = [[red giant branch]]<ref name=GaiaDR3/> | class = {{nowrap|K2.5 III Fe-2}}<ref name=perkins1989/> + {{nowrap|A8–9 V<ref name=Griffin1990/>}} | b-v = {{Val|1.312|0.003}}<ref name=Anderson2012/> | u-b = | variable = }} {{Starbox astrometry | radial_v = {{Val|3.38|0.30}}<ref name=Anderson2012/> | prop_mo_ra = −32.393<ref name=GaiaDR3/> | prop_mo_dec = −4.449<ref name=GaiaDR3/> | parallax = 6.6159 | p_error = 0.4238 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = −1.35<ref name=Anderson2012/> }} {{Starbox orbit | reference = <ref name=Griffin1990/> | primary = <!--Primary name --> | name = <!--Companion name--> | period = <!--Period (in years)--> | period_unitless = {{Val|561.7|0.3|u=days}} | axis = <!--Semimajor axis (in arcseconds)--> | axis_unitless = <!--Semimajor axis (no units provided by template)--> | eccentricity = {{Val|0.262|0.017}} | inclination = <!--Inclination (in degrees)--> | node = <!--Longitude of node (in degrees)--> | periastron = {{Val|45525|5|u=MJD}} | periarg = {{Val|9|4}} | periarg_primary = <!--Argument of periastron (in degrees), primary --> | k1 = {{Val|6.90|0.12}} | k2 = <!-- Velocity semi-amplitude (secondary in SB2), in km/s --> }} {{Starbox detail | mass = 1.28<ref name=khalatyan2024/> | radius = 33<ref name=fetherolf2023/> | luminosity = 316<ref name=fetherolf2023/> | temperature = 4,134<ref name=kordopatis2023/> | gravity = 1.43<ref name=kordopatis2023/> | metal_fe = −0.22<ref name=khalatyan2024/> | rotational_velocity = 1.7<ref name=DeMedeiros2002/> | age_gyr = 2.2<ref name=kordopatis2023/> }} {{Starbox catalog | names = {{odlist | F=6 Dra | BD=+70°705 | HD=109551 | HIP=61384 | HR=4795 | SAO=7600 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad=6+Dra }} {{Starbox end}}
[[Image:6 Draconis.jpg|thumb|left|6 Draconis(center) and [[Kappa Draconis|κ Draconis]] (below)]] '''6 Draconis''' is a single-lined [[spectroscopic binary]]<ref name=Griffin1990/> [[star]] system in the northern [[constellation]] of [[Draco (constellation)|Draco]], located about 430 [[light year]]s away from the Sun. It is visible to the naked eye as an orange-hued star with an [[apparent visual magnitude]] of 4.95.<ref name=Anderson2012/> The system is moving further from the Earth with a heliocentric [[radial velocity]] of 3 km/s.<ref name=Anderson2012/>
The variable [[radial velocity]] of this star system was announced by [[William Wallace Campbell|W. W. Campbell]] in 1922. Griffin et al. (1990) found an [[orbital period]] of {{Convert|561.7|days|years|sigfig=2|disp=out}} and an [[orbital eccentricity|eccentricity]] of 0.26. The primary has an "''a'' sin ''i''" value of {{Convert|51.4|Gm|AU|lk=on|abbr=on|sigfig=2}}, where ''a'' is the [[semimajor axis]] and ''i'' is the (unknown) [[orbital inclination]]. This value provides a lower bound on the actual semimajor axis, which is one half of the longest dimension of their elliptical orbit.<ref name=Griffin1990/>
The visible component is an [[stellar evolution|evolved]] [[giant star]] with a [[stellar classification]] of {{nowrap|K2.5 III Fe-2}},<ref name=perkins1989/> where the suffix notation indicates a pronounced underabundance of iron in the [[stellar spectrum|spectrum]]. The measured [[angular diameter]] of this star, after correction for [[limb darkening]], is {{val|2.54|0.04|ul=mas}}.<ref name=Richichi2005/> At its estimated distance, this yields a physical size of about 33 times the [[Solar radius|radius of the Sun]].<ref name=fetherolf2023/> It is radiating 316 times the [[Sun's luminosity]]<ref name=fetherolf2023/> from its enlarged [[photosphere]] at an [[effective temperature]] of {{val|fmt=commas|4134|ul=K}}.<ref name=kordopatis2023/> The companion is most likely an [[A-type main-sequence star]] with a class of A8–9 V.<ref name=Griffin1990/>
==References== <references> <ref name=SIMBAD>{{cite simbad | title=6 Dra | access-date=2019-01-23 }}</ref>
<ref name=GaiaDR3>{{Cite Gaia DR3|1683112784684915456}}</ref>
<ref name=DeMedeiros2002>{{citation | title=The Rotation of Binary Systems with Evolved Components | display-authors=1 | last1=De Medeiros | first1=J. R. | last2=Da Silva | first2=J. R. P. | last3=Maia | first3=M. R. G. | journal=The Astrophysical Journal | postscript=. | volume=578 | issue=2 | pages=943–950 | date=October 2002 | doi=10.1086/342613 | bibcode=2002ApJ...578..943D | arxiv=astro-ph/0207288| s2cid=16196039 }}</ref>
<ref name=perkins1989>{{citation | title=The Perkins catalog of revised MK types for the cooler stars | last1=Keenan | first1=Philip C. | last2=McNeil | first2=Raymond C. | journal=Astrophysical Journal Supplement Series | volume=71 | pages=245 | year=1989 | postscript=. | bibcode=1989ApJS...71..245K | doi=10.1086/191373 }}</ref>
<ref name=Griffin1990>{{citation | display-authors=1 | last1=Griffin | first1=R. F. | last2=Eitter | first2=J. J. | last3=Reimers | first3=D. | title= The spectroscopic orbit of 6 Draconis | journal=Journal of Astrophysics and Astronomy | volume=11 | page=255 | date=June 1990 | issue=2 | doi=10.1007/BF02715020 | bibcode=1990JApA...11..255G | s2cid=120297735 }}</ref>
<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>
<ref name=Richichi2005>{{citation | last1=Richichi | first1=A. | last2=Percheron | first2=I. | last3=Khristoforova | first3=M. | title=CHARM2: An updated Catalog of High Angular Resolution Measurements | journal=Astronomy and Astrophysics | postscript=. | volume=431 | issue=2 | pages=773–777 | date=February 2005 | doi=10.1051/0004-6361:20042039 | bibcode=2005A&A...431..773R | doi-access=free }}</ref>
<ref name=kordopatis2023>{{cite journal | title=Stellar ages, masses, extinctions, and orbital parameters based on spectroscopic parameters of Gaia DR3 | last1=Kordopatis | first1=G. | last2=Schultheis | first2=M. | last3=McMillan | first3=P. J. | last4=Palicio | first4=P. A. | last5=De Laverny | first5=P. | last6=Recio-Blanco | first6=A. | last7=Creevey | first7=O. | last8=Álvarez | first8=M. A. | last9=Andrae | first9=R. | last10=Poggio | first10=E. | last11=Spitoni | first11=E. | last12=Contursi | first12=G. | last13=Zhao | first13=H. | last14=Oreshina-Slezak | first14=I. | last15=Ordenovic | first15=C. | last16=Bijaoui | first16=A. | display-authors=1 | journal=Astronomy and Astrophysics | date=2023 |volume=669 |pages=A104 | doi=10.1051/0004-6361/202244283 |arxiv=2206.07937 | bibcode=2023A&A...669A.104K }}</ref>
<ref name=khalatyan2024>{{cite journal |last1=Khalatyan |first1=A. |last2=Anders |first2=F. |last3=Chiappini |first3=C. |last4=Queiroz |first4=A. B. A. |last5=Nepal |first5=S. |last6=Dal Ponte |first6=M. |last7=Jordi |first7=C. |last8=Guiglion |first8=G. |last9=Valentini |first9=M. |last10=Torralba Elipe |first10=G. |last11=Steinmetz |first11=M. |last12=Pantaleoni-González |first12=M. |last13=Malhotra |first13=S. |last14=Jiménez-Arranz |first14=Ó. |last15=Enke |first15=H. |last16=Casamiquela |first16=L. |last17=Ardèvol |first17=J. |title=Transferring spectroscopic stellar labels to 217 million ''Gaia'' DR3 XP stars with SHBoost |journal=Astronomy & Astrophysics |date=2024 |volume=691 |pages=A98 |doi=10.1051/0004-6361/202451427 |arxiv=2407.06963 |bibcode=2024A&A...691A..98K }}</ref>
<ref name=fetherolf2023>{{citation |postscript=. |bibcode=2023ApJS..268....4F |title=Variability Catalog of Stars Observed during the TESS Prime Mission |last1=Fetherolf |first1=Tara |last2=Pepper |first2=Joshua |last3=Simpson |first3=Emilie |last4=Kane |first4=Stephen R. |last5=Močnik |first5=Teo |last6=English |first6=John Edward |last7=Antoci |first7=Victoria |last8=Huber |first8=Daniel |last9=Jenkins |first9=Jon M. |last10=Stassun |first10=Keivan |last11=Twicken |first11=Joseph D. |last12=Vanderspek |first12=Roland |last13=Winn |first13=Joshua N. |journal=The Astrophysical Journal Supplement Series |date=2023 |volume=268 |issue=1 |page=4 |doi=10.3847/1538-4365/acdee5 |doi-access=free |arxiv=2208.11721 }}</ref>
</references>
{{Stars of Draco}}
[[Category:K-type giants]] [[Category:A-type main-sequence stars]] [[Category:Spectroscopic binaries]] [[Category:Draco (constellation)]] [[Category:Durchmusterung objects]] [[Category:Flamsteed objects|Draconis, 06]] [[Category:Henry Draper Catalogue objects|109551]] [[Category:Hipparcos objects|061384]] [[Category:Bright Star Catalogue objects|4795]]