{{Short description|Star in the constellation Centaurus}} {{about|C<sup>1</sup> Centauri|c<sup>1</sup> Centauri|HD 129456|other stars with this [[Bayer designation]]|C Centauri}} {{Starbox begin | name = C<sup>1</sup> Centauri }} {{Starbox image | image = [[Image:V763CenLightCurve.png|250px]] | caption = A [[light curve]] for V763 Centauri, plotted from ''[[Hipparcos]]'' data<ref name=HipDataAccess/> }} {{Starbox observe | epoch = J2000.0 | constell = [[Centaurus]] | ra = {{RA|11|35|13.28134}}<ref name=GaiaDR2/> | dec = {{DEC|−47|22|21.2888}}<ref name=GaiaDR2/> | appmag_v = +5.64<ref name=Anderson2012/> }} {{Starbox character | type = [[Asymptotic giant branch|AGB]]<ref name=Eggen1992/> | class = M3/4III<ref name=houk1978/> | b-v = {{Val|+1.682|0.019}}<ref name=Anderson2012/> | u-b = | variable = [[slow irregular variable|Lb]]<ref name=Samus2017/> }} {{Starbox astrometry | radial_v = {{Val|+21.07|0.29}}<ref name=GaiaDR2/> | prop_mo_ra = -87.503<ref name=GaiaDR2/> | prop_mo_dec = -6.988<ref name=GaiaDR2/> | parallax = 5.4236 | p_error = 0.1476 | parallax_footnote = <ref name=GaiaDR2/> | absmag_v = −1.05<ref name=Anderson2012/> }} {{Starbox detail | source = | mass = | radius = {{Val|64.7|5.9|4.3}}<ref name=GaiaDR2/> | luminosity = {{Val|754|24}}<ref name=GaiaDR2/> | temperature = {{Val|3761|130|161|fmt=commas}}<ref name=GaiaDR2/> | metal_fe = | gravity = | rotational_velocity = | age_myr = }} {{Starbox catalog | names = {{odlist | V=V763&nbsp;Centauri | B=C<sup>1</sup>&nbsp;Cen | CD=−46°7199 | HD=100733 | HIP=56518 | HR=4463 | SAO=222887 | GC=15886 | CCDM=J11352-4722 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = HD+100733 }} {{Starbox end}}

'''C<sup>1</sup> Centauri''' is a single<ref name=Eggleton2008/> [[star]] in the southern [[constellation]] of [[Centaurus]]. It has the [[variable star designation]] '''V763&nbsp;Centauri''', while ''C<sup>1</sup> Centauri'' is the [[Bayer designation]]. The star has a red hue and is dimly visibly to the [[naked eye]] with an [[apparent visual magnitude]] that fluctuates around +5.64.<ref name=Anderson2012/> It is located at a distance of approximately 600&nbsp;[[light year]]s based on [[stellar parallax|parallax]], and has an [[absolute magnitude]] of −1.05.<ref name=Anderson2012/> It is drifting further away with a [[radial velocity]] of +21&nbsp;km/s.<ref name=GaiaDR2/> At one time it was a candidate member of the [[Zeta Herculis Moving Group]] but has since been excluded.<ref name=Eggen1971/>

This object is an aging [[red giant]] star on the [[asymptotic giant branch]]<ref name=Eggen1992/> with a [[stellar classification]] of M3/4III.<ref name=houk1978/> Samus et al. (2017) classify this as a [[slow irregular variable]] of sub-type Lb and its brightness varies from magnitude +5.52 down to +5.82.<ref name=Samus2017/> It was previously classified as a [[semiregular variable]] of sub-type SRb.<ref name=Kerschbaum1994/> With the supply of hydrogen and helium at its [[stellar core|core]] exhausted, the star has expanded until now it has 65 times the [[radius of the Sun]]. It is radiating 754 times the [[luminosity of the Sun]] from its [[photosphere]] at an [[effective temperature]] of 3,761&nbsp;K.<ref name=GaiaDR2/>

== References == {{Reflist|colwidth=30em|refs=

<ref name=GaiaDR2>{{cite DR2|5372183546686006400}}</ref>

<ref name=SIMBAD>{{cite simbad | title=HD 100733 | access-date=2020-03-02}}</ref>

<ref name=Anderson2012>{{citation | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | arxiv=1108.4971 | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | postscript=. | doi=10.1134/S1063773712050015 | s2cid=119257644 }}</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 | date=September 2008 | bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | s2cid=14878976 | postscript=. }}</ref>

<ref name=HipDataAccess>{{cite web |title=Hipparcos Tools Interactive Data Access |url=https://www.cosmos.esa.int/web/hipparcos/interactive-data-access |website=Hipparcos |publisher=ESA |access-date=8 December 2021}}</ref>

<ref name=Samus2017>{{citation | display-authors=1 | last1=Samus | first1=N. N. | last2=Kazarovets | first2=E. V. | last3=Durlevich | first3=O. V. | last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N. | title=General Catalogue of Variable Stars | version=5.1 | journal=Astronomy Reports | year=2017 | volume=61 | issue=1 | pages=80–88 | bibcode=2017ARep...61...80S | postscript=. | doi=10.1134/S1063772917010085 | s2cid=125853869 }}</ref>

<ref name=houk1978>{{citation | last1=Houk | first1=Nancy | title=Michigan catalogue of two-dimensional spectral types for the HD stars | volume=2 | year=1978 | location=Ann Arbor | publisher=Dept. of Astronomy, University of Michigan | bibcode=1978mcts.book.....H | postscript=. }}</ref>

<ref name=Kerschbaum1994>{{citation | title=Semiregular variables of types SRa and SRb. New JHKL'M-photometry for 200 stars | last1=Kerschbaum | first1=F. | last2=Hron | first2=J. | journal=Astronomy and Astrophysics Supplement | volume=106 | pages=397–411 | date=September 1994 | bibcode=1994A&AS..106..397K | postscript=. }}</ref>

<ref name=Eggen1992>{{citation | last1=Eggen | first1=Olin J. | title=Asymptotic giant branch stars near the sun | journal=Astronomical Journal | postscript=. | volume=104 | issue=1 | pages=275–313 | date=July 1992 | doi=10.1086/116239 | bibcode=1992AJ....104..275E }}</ref>

<ref name=Eggen1971>{{citation | title=The ζ Herculis, σ Puppis, ∈ Indi, and η Cephei Groups of Old Disk Population Stars | last=Eggen | first=O. J. | postscript=. | journal=Publications of the Astronomical Society of the Pacific | volume=83 | issue=493 | page=251 | date=June 1971 | doi=10.1086/129119 | bibcode=1971PASP...83..251E | doi-access=free }}</ref>

}}

{{Stars of Centaurus}}

[[Category:M-type giants]] [[Category:Semiregular variable stars]] [[Category:Slow irregular variables]] [[Category:Centaurus]] [[Category:Bayer objects|Centauri, C1]] [[Category:Durchmusterung objects|CD-46 07199]] [[Category:Henry Draper Catalogue objects|100733]] [[Category:Hipparcos objects|056518]] [[Category:Bright Star Catalogue objects|4463]] [[Category:Objects with variable star designations|Centauri, V763]]