{{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=7 Draconis |x=920|y=460 }} | caption = Location of 7 Draconis (circled in red) }} {{Starbox observe | epoch = [[J2000.0]] | equinox = [[J2000.0]] ([[International Celestial Reference System|ICRS]]) | constell = [[Draco (constellation)|Draco]] | ra = {{RA|12|47|34.34473}}<ref name=GaiaDR2/> | dec = {{DEC|+66|47|25.0977}}<ref name=GaiaDR2/> | appmag_v = 5.43<ref name=Anderson2012/> }} {{Starbox character | class = K5 III<ref name=Anderson2012/> | b-v = {{Val|1.567|0.006}}<ref name=Anderson2012/> | u-b = | r-i = | variable = }} {{Starbox astrometry | radial_v = {{Val|+11.33}}<ref name=SIMBAD/> | prop_mo_ra = 6.674<ref name=GaiaDR2/> | prop_mo_dec = −6.498<ref name=GaiaDR2/> | parallax = 4.1601 | p_error = 0.1056 | parallax_footnote = <ref name=GaiaDR2/> | absmag_v = −1.35<ref name=Anderson2012/> }} {{Starbox detail | mass = 1.13<ref name=khalatyan2024/> | radius = 63<ref name=tic/> | luminosity = 1,024<ref name=Anderson2012/> | temperature = 3,903<ref name=kordopatis2023/> | gravity = 1.04<ref name=kordopatis2023/> | metal_fe = | rotational_velocity = | age_gyr = 2.3<ref name=kordopatis2023/> }} {{Starbox catalog | names = {{odlist | name=Tianyi | F=7 Dra | BD=+67°764 | FK5=3020 | HD=111335 | HIP=62423 | HR=4863 | SAO=15902 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = 7+Dra }} {{Starbox end}} '''7 Draconis''', also named '''Tianyi''' {{IPAc-en|t|i|æ|n|ˈ|j|iː}},<ref name=IAU-LSN/> is a single<ref name=Eggleton2008/> [[star]] in the northern [[circumpolar constellation]] of [[Draco (constellation)|Draco]]. It is visible to the naked eye as a faint orange-hued star with a [[stellar classification]] of 5.43.<ref name=Anderson2012/> Based upon an annual [[parallax]] shift of {{Val|4.16|ul=mas}} as seen from the [[Earth]],<ref name=GaiaDR2/> the star is located approximately 780 [[light-year]]s from the [[Sun]].
This is an [[stellar evolution|evolved]] [[giant star]] with a [[stellar classification]] of K5 III.<ref name=Anderson2012/> The measured [[angular diameter]] of this star, after correction for [[limb darkening]], is {{val|2.61|0.03|ul=mas}}.<ref name=Richichi2005/> At its estimated distance, this yields a physical size of about 63 times the [[Solar radius|radius of the Sun]].<ref name=tic/> It is radiating about 1,024 times the [[Sun's luminosity]]<ref name=Anderson2012/> from its enlarged [[photosphere]] at an [[effective temperature]] of {{val|fmt=commas|3903|ul=K}}.<ref name=kordopatis2023/>
== Nomenclature == 7 Draconis is the star's [[Flamsteed designation]].
The star bore the [[Chinese star names|traditional Chinese name]] of ''Tianyi'',<ref name="Bonnet-Bidaud2009"/><ref name="TriRpt18">{{cite web | url=https://exopla.net/wp-content/uploads/2025/04/2018_WGSN-triennial-report-2015-2018.pdf | page=7 | title=WG Triennial Report (2015-2018) - Star Names |access-date=2018-07-14}}</ref> from 天乙 (''Tiān Yǐ'') or 天一 (''Tiān Yī'', the Celestial Great One), a deity in Taoism. Alternatively, Tianyi may refer to [[10 Draconis]]{{refn|[[Stellarium (software)|Stellarium]], citing Yi Shitong, 1981<ref name=Yi1981/>}} or [[κ Draconis]],<ref name="Yang2024"/> with 7 and [[8 Draconis]] forming ''Neichu'', representing a private kitchen.<ref name="Ridpath"/> In 2016, the [[International Astronomical Union]] organized a [[IAU Working Group on Star Names|Working Group on Star Names]] (WGSN)<ref name=WGSN/> to catalogue and standardize proper names for stars. The WGSN approved the name ''Tianyi'' for this star on 30 June 2017 and it is now so entered in the IAU Catalog of Star Names.<ref name="IAU-CSN-new"/>
==References== <references> <ref name=SIMBAD>{{cite simbad | title=6 Dra | access-date=2019-01-23 }}</ref>
<ref name=GaiaDR2>{{Cite Gaia DR2|1683112784684915456}}</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=Eggleton2008>{{citation | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | title=A catalogue of multiplicity among bright stellar systems | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=389 | issue=2 | pages=869–879 | year=2008 | arxiv=0806.2878 | bibcode=2008MNRAS.389..869E | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | s2cid=14878976 | postscript=. }}</ref>
<ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |access-date=16 December 2017 |archive-url=https://web.archive.org/web/20250224122744/https://www.iau.org/public/themes/naming_stars/ |archive-date=24 February 2025 |url-status=dead}}</ref>
<ref name=WGSN>{{Cite web |url=https://www.iau.org/science/scientific_bodies/working_groups/280/ |title=International Astronomical Union {{!}} IAU |website=www.iau.org |access-date=2018-01-16}}</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="IAU-CSN-new">{{cite web |title=IAU Catalog of Star Names |url=https://exopla.net/star-names/modern-iau-star-names/ |access-date=10 May 2025}}</ref>
<ref name="Ridpath">{{cite web |last=Ridpath |first=Ian |author-link=Ian Ridpath |title=Star Tales - Draco |url=http://ianridpath.com/startales/draco.html |access-date=10 May 2025}}</ref>
<ref name="Bonnet-Bidaud2009">{{cite journal |last1=Bonnet-Bidaud |first1=Jean-Marc |last2=Praderie |first2=Françoise |last3=Whitfield |first3=Susan |date=March 2009 |title=The Dunhuang Chinese sky: A comprehensive study of the oldest known star atlas |journal=[[Journal of Astronomical History and Heritage]] |volume=12 |issue=1 |pages=39–59 |doi= 10.3724/SP.J.1440-2807.2009.01.04|arxiv=0906.3034 |bibcode=2009JAHH...12...39B}}</ref>
<ref name="Yang2024">{{cite journal |last1=Yang |first1=Bo-Shun |last2=Hoffmann |first2=Susanne M. |date=December 2024 |title=Identification of Z Cam's Historical Counterpart: The Quest for an Ancient Nova |journal=[[Research in Astronomy and Astrophysics]] |volume=24 |issue=12 |pages=125004 |doi=10.1088/1674-4527/ad89aa |arxiv=2410.19010 |bibcode=2024RAA....24l5004Y}}</ref>
<ref name=Yi1981>{{cite book|script-title=zh:中西对照恒星图表|lang=zh|trans-title=Atlas Comparing Chinese and Western Star Maps and Catalogues|last=Yi|first=Shitong|date=April 1981|publisher=科学出版社}}</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=tic>{{cite journal | display-authors=1 | last1=Stassun | first1=Keivan G. | last2=Oelkers | first2=Ryan J. | last3=Paegert | first3=Martin | last4=Torres | first4=Guillermo | last5=Pepper | first5=Joshua | last6=Lee | first6=Nathan De | last7=Collins | first7=Kevin | last8=Latham | first8=David W. | last9=Muirhead | first9=Philip S. | last10=Chittidi | first10=Jay | last11=Rojas-Ayala | first11=Bárbara | last12=Fleming | first12=Scott W. | last13=Rose | first13=Mark E. | last14=Tenenbaum | first14=Peter | last15=Ting | first15=Eric B. | last16=Kane | first16=Stephen R. | last17=Barclay | first17=Thomas | last18=Bean | first18=Jacob L. | last19=Brassuer | first19=C. E. | last20=Charbonneau | first20=David | last21=Ge | first21=Jian | last22=Lissauer | first22=Jack J. | last23=Mann | first23=Andrew W. | last24=McLean | first24=Brian | last25=Mullally | first25=Susan | last26=Narita | first26=Norio | last27=Plavchan | first27=Peter | last28=Ricker | first28=George R. | last29=Sasselov | first29=Dimitar | last30=Seager | first30=S. | last31=Sharma | first31=Sanjib | last32=Shiao | first32=Bernie | last33=Sozzetti | first33=Alessandro | last34=Stello | first34=Dennis | last35=Vanderspek | first35=Roland | last36=Wallace | first36=Geoff | last37=Winn | first37=Joshua N. | title=The Revised TESS Input Catalog and Candidate Target List | journal=The Astronomical Journal | volume=158 | issue=4 | date=2019-10-01 | issn=0004-6256 | doi=10.3847/1538-3881/ab3467 | doi-access=free | page=138| arxiv=1905.10694 | bibcode=2019AJ....158..138S }}</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>
</references>
{{Stars of Draco|state=collapsed}}
{{Authority control}}
[[Category:K-type giants]] [[Category:Draco (constellation)]] [[Category:Flamsteed objects|Draconis, 07]] [[Category:Henry Draper Catalogue objects|111335]] [[Category:Hipparcos objects|62423]] [[Category:Bright Star Catalogue objects|4863]] [[Category:Stars with proper names|Tianyi]]