8 Draconis

{{Short description|White-hued chemically unusual star in the constellation Draco}}

{{Starbox begin

| name = 8 Draconis

}}

{{Starbox image

| image = 250px

| caption = A light curve for IR Draconis, adapted from Aerts et al. (1998)

}}

{{Starbox observe

| epoch = J2000.0

| equinox = J2000.0 (ICRS)

| constell = Draco

| ra = {{RA|12|55|28.550015}}

| dec = {{DEC|+65|26|18.5079}}

| appmag_v = 5.225

}}

{{Starbox character

| class = F1VmA7(n)

| b-v = {{Val|0.303|0.005}}

| u-b =

| r-i =

| variable = Gamma Doradus

}}

{{Starbox astrometry

| radial_v = {{Val|+9.0}}

| prop_mo_ra = −4.235

| prop_mo_dec = −30.174

| parallax = 34.0276

| p_error = 0.0922

| parallax_footnote =

| absmag_v = 2.90

}}

{{Starbox detail

| source =

| mass = 1.56

| radius = 1.50

| luminosity = 5.75

| temperature = 7,129

| gravity = 4.01

| metal_fe = −0.14

| rotational_velocity = 119.6

| age_myr = {{Val|250|200}}

}}

{{Starbox catalog

| names = {{odlist | name=Taiyi | V=IR Draconis | F=8 Dra | BD=+66°778 | FK5=486 | HD=112429 | HIP=63076 | HR=4916 | SAO=15941 }}

}}

{{Starbox reference

| Simbad = 8+Dra

}}

8 Draconis, formally named Taiyi {{IPAc-en|,|t|ai|'|j|iː}}, is a single star in the northern circumpolar constellation of Draco. Based upon an annual parallax shift of 34.14 mas as seen from the Earth, the star is located approximately 96 light-years from the Sun. It is moving further away with a heliocentric radial velocity of +9 km/s, having come within {{Convert|12.46|pc|ly|disp=out}} some 2.6 million years ago.

This is an F-type main-sequence star with a stellar classification of F1VmA7(n). It is a Gamma Doradus variable star with a brightness variation of about one tenth of a magnitude. 8 Dra has a relatively high rate of rotation, showing a projected rotational velocity of 120 km/s. The star has 1.56 times the mass of the Sun and 1.50 times the Sun's radius. It is radiating 5.75 times the Sun's luminosity from its photosphere at an effective temperature of 7,129 K. An infrared excess has been detected at wavelengths of 24 and 70μm, which suggests the presence of a circumstellar disk orbiting the star.

Nomenclature

8 Draconis is the star's Flamsteed designation. It also received the variable star designation IR Draconis in 2000, after its variability had been discovered using Hipparcos photometry.

The star bore the traditional Chinese name of Taiyi,{{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}} from 太乙 (Tài Yǐ) or 太一 (Tài Yī, the Great One), both of which refer to Tao. Alternatively, Taiyi may refer to HD 119476{{cn|date=May 2025|reason=Poorly sourced identification appearing elsewhere on English and Chinese Wikipedias}} or 4 Draconis, with 7 and 8 Draconis forming Neichu, representing a private kitchen. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Taiyi for this star on 30 June 2017 and it is now so entered in the IAU Catalog of Star Names.

References

{{reflist|refs=

{{cite journal |last1=Aerts |first1=C. |last2=Eyer |first2=L. |last3=Kestens |first3=E. |title=The discovery of new γ Doradus stars from the HIPPARCOS mission |journal=Astronomy and Astrophysics |date=September 1998 |volume=337 |pages=790–796 |bibcode=1998A&A...337..790A |url=https://ui.adsabs.harvard.edu/abs/1998A&A...337..790A |access-date=4 January 2022}}

{{citation

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| bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 }}

{{citation | last1=Schröder | first1=C. | last2=Reiners | first2=Ansgar | last3=Schmitt | first3=Jürgen H. M. M. | title=Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo | journal=Astronomy and Astrophysics | volume=493 | issue=3 | pages=1099–1107 | date=January 2009 | doi=10.1051/0004-6361:200810377 | bibcode=2009A&A...493.1099S | doi-access=free | url=http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/9690/aa10377-08.pdf?sequence=2 }}{{Dead link|date=July 2023 |bot=InternetArchiveBot |fix-attempted=yes }}

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| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015

| arxiv=1108.4971 | s2cid=119257644 | postscript=. }}

{{Cite web

|url=https://iau.org/WG280

|title=International Astronomical Union {{!}} IAU

|website=www.iau.org

|access-date=2025-04-09}}

{{citation

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| title=New Debris Disks Around Young, Low-Mass Stars Discovered with the Spitzer Space Telescope

| journal=The Astrophysical Journal

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| doi=10.1088/0004-637X/698/2/1068 | postscript=.

| bibcode=2009ApJ...698.1068P | arxiv=0904.0819 | s2cid=51417657 }}

{{cite journal|bibcode=2007A&A...474..653V|title=Validation of the new Hipparcos reduction|journal=Astronomy and Astrophysics|volume=474|issue=2|pages=653–664|last1=Van Leeuwen|first1=F|year=2007|doi=10.1051/0004-6361:20078357|arxiv=0708.1752|s2cid=18759600}}

{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}

{{cite journal|bibcode= 1953GCRV..C......0W |title= General catalogue of stellar radial velocities |journal= Washington |last1= Wilson |first1= Ralph Elmer |year= 1953 }}

{{cite journal|bibcode=2003AJ....126.2048G|title=Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I|journal=The Astronomical Journal|volume=126|issue=4|pages=2048|last1=Gray|first1=R. O|last2=Corbally|first2=C. J|last3=Garrison|first3=R. F|last4=McFadden|first4=M. T|last5=Robinson|first5=P. E|year=2003|doi=10.1086/378365|arxiv=astro-ph/0308182|s2cid=119417105}}

{{cite journal|bibcode=2000A&A...355L..27H|title=The Tycho-2 catalogue of the 2.5 million brightest stars|journal=Astronomy and Astrophysics|volume=355|pages=L27|last1=Høg|first1=E|last2=Fabricius|first2=C|last3=Makarov|first3=V. V|last4=Urban|first4=S|last5=Corbin|first5=T|last6=Wycoff|first6=G|last7=Bastian|first7=U|last8=Schwekendiek|first8=P|last9=Wicenec|first9=A|year=2000|url=https://ui.adsabs.harvard.edu/abs/2000A%26A...355L..27H/abstract}}

{{cite web

|url=https://theskylive.com/sky/stars/taiyi-8-draconis-star

|title=The Sky Live

|website=theskylive.com

|access-date=2025-04-09}}

{{cite web |title=IAU Catalog of Star Names |url=https://exopla.net/star-names/modern-iau-star-names/ |access-date=10 May 2025}}

{{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}}

{{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}}

{{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}}

}}

Category:F-type main-sequence stars

Category:Gamma Doradus variables

Category:Circumstellar disks

Category:Draco (constellation)