{{short description|Star in the constellation Centaurus}} {{Starbox begin}} {{Starbox observe | epoch = J2000.0 | constell = [[Centaurus]]<ref name=Anderson_Francis_2012/> | ra = {{RA|14|46|33.636}}<ref name=GaiaDR3/> | dec = {{DEC|−32|10|15.27}}<ref name=GaiaDR3/> | appmag_v = {{val|8.22|to|8.80}}<ref name=Samus_et_al_2017/> }} {{Starbox character | type = | class = G5p I–III<ref name=Hoffmeister_1957/> | b-v = 0.600{{±|0.020}}<ref name=Anderson_Francis_2012/> | u-b = | variable = [[BL Herculis variable|BL Her]]<ref name=Samus_et_al_2017/> }} {{Starbox astrometry | radial_v = −4.95{{±|3.95}}<ref name=GaiaDR3/> | prop_mo_ra = 4.145 | prop_mo_dec = −1.914 | pm_footnote = <ref name=GaiaDR3/> | parallax = 1.7286 | p_error = 0.0224 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = }} {{Starbox detail | source = | mass = 0.49<ref name=Petersen_1981/> | radius = 9.9<ref name=Petersen_1981/> | luminosity = | gravity = 2.2<ref name=Kovtyukh_et_al_2018/> | temperature = 6,060<ref name=Kovtyukh_et_al_2018/> | metal_fe = 0.01<ref name=Kovtyukh_et_al_2018/> | rotation = | rotational_velocity = | age_gyr = }} {{Starbox catalog | names = {{odlist | V=V553 Cen | CD=−31° 11449 | HD=129981 | HIP=72257 | PPM=293050 | SAO=205930 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = V553+Cen }} {{Starbox end}}
'''V553 Centauri''' is a [[variable star]] in the southern [[constellation]] of [[Centaurus]], abbreviated V553 Cen. It ranges in brightness from an [[apparent visual magnitude]] of 8.22 down to 8.80 with a period of 2.06 days.<ref name=Samus_et_al_2017/> At that magnitude, it is too dim to be visible to the [[naked eye]]. Based on [[stellar parallax|parallax]] measurements,<ref name=GaiaDR3/> it is located at a distance of approximately 1,890 [[light year]]s from the [[Sun]].
==Observations== [[File:V553CenLightCurve.png|thumb|left|A light curve for V553 Centauri, plotted from ''[[Transiting Exoplanet Survey Satellite|TESS]]'' data<ref name=MAST/>]] The variability of this star was announced in 1936 by [[Cuno Hoffmeister|C. Hoffmeister]].<ref name=Hoffmeister_1936/> In 1957, he determined it to be a [[Classical Cepheid variable|Delta Cepheid variable]] with a magnitude range of {{val|8.3|to|8.6}} and a periodicity of {{val|2.06119|u=days|fmt=commas}}. The observers [[Michael William Feast|M. W. Feast]] and [[George Howard Herbig|G. H. Herbig]] noted a peculiar [[stellar spectrum|spectrum]] with strong [[absorption line]]s of the molecules [[Methylidyne radical|CH]] and [[Cyanide|CN]], while neutral iron lines are unusually weak. They found a [[stellar classification]] of G5p I–III.<ref name=Hoffmeister_1957/>
In 1972, [[Thomas Harry Hope Lloyd-Evans|T. Lloyd-Evans]] and associates found the star's prominent bands of C<sub>2</sub>, CH, and CN varied with the Cepheid phase, being strongest at minimum. They suggested a large overabundance of carbon in the star's atmosphere.<ref name=Lloyd_Evans_et_al_1972/> Chemical analysis of the atmosphere in 1979 showed a [[metallicity]] close to solar, with an enhancement of carbon and nitrogen. It was proposed that V553 Cen is an evolved [[RR Lyrae variable]] and is now positioned above the [[horizontal branch]] on the [[HR diagram]].<ref name=Cotrell_1979/> V553 Cen is classified as a [[BL Herculis variable]], being a low–mass [[type II Cepheid]] with a period between {{val|1|and|6|u=days}}. As with other variables of this type, it displays a secondary bump on its [[light curve]].<ref name=Petersen_1981/> It is a member of a small group of carbon Cepheids, and is one of the brightest stars of that type.<ref name=Wallerstein_Gonzalez_1996/>
V553 Cen does not appear to have a companion.<ref name=Wallerstein_Gonzalez_1998/> From the luminosity and shape of the [[light curve]], [[stellar model]]s from 1981 suggest a mass equal to 49% of the Sun's with 9.9 times the radius of the Sun.<ref name=Petersen_1981/> Further analysis of the spectrum showed that oxygen is not enhanced, but sodium may be moderately enhanced.<ref name=Wallerstein_Gonzalez_1996/> There is no evidence of [[s-process]] enhancement of elements. Instead, the abundance peculiarities are the result of [[Nuclear fusion|nuclear reaction]] sequences followed by [[dredge-up]].<ref name=Wallerstein_Gonzalez_1998/> In particular, these are the product of [[Triple-alpha process|triple-α]], CN, ON, and perhaps some Ne–Na reactions.<ref name=Wallerstein_Gonzalez_1996/>
==See also== * [[Carbon star]]<ref name=Wallerstein_Gonzalez_1996/> * [[RT Trianguli Australis]]
== References == <references>
<ref name=SIMBAD>{{cite simbad | title=V553 Cen | access-date=2024-12-31 | postscript=. | mode = cs2 }}</ref>
<ref name=GaiaDR3>{{Cite Gaia DR3 | 5047189109469319680}}</ref>
<ref name=Anderson_Francis_2012>{{citation | postscript=. | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | title=XHIP: An extended hipparcos compilation | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | arxiv=1108.4971 | doi=10.1134/S1063773712050015 | s2cid=119257644 }}</ref>
<ref name=MAST>{{cite web | title=MAST: Barbara A. Mikulski Archive for Space Telescopes | url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html | publisher=Space Telescope Science Institute | access-date=5 January 2025}}</ref>
<ref name=Samus_et_al_2017>{{citation | postscript=. | title=General Catalogue of Variable Stars | 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. | version=GCVS 5.1 | journal=Astronomy Reports | year=2017 | volume=61 | issue=1 | pages=80–88 | doi=10.1134/S1063772917010085 | bibcode=2017ARep...61...80S | s2cid=255195566 }}</ref>
<ref name=Kovtyukh_et_al_2018>{{citation | postscript=. | title=Metal-poor Type II Cepheids with Periods Less Than Three Days | display-authors=1 | last1=Kovtyukh | first1=V. | last2=Wallerstein | first2=G. | last3=Yegorova | first3=I. | last4=Andrievsky | first4=S. | last5=Korotin | first5=S. | last6=Saviane | first6=I. | last7=Belik | first7=S. | last8=Davis | first8=C. E. | last9=Farrell | first9=E. M. | journal=Publications of the Astronomical Society of the Pacific | volume=130 | issue=987 | date=May 2018 | doi=10.1088/1538-3873/aaacf7 | arxiv=1803.05041 | bibcode=2018PASP..130e4201K }}</ref>
<ref name=Hoffmeister_1936>{{citation | postscript=. | title=71 südlicheneue Veränderliche | last=Hoffmeister | first=Cuno | journal=Astronomische Nachrichten | volume=258 | page=39 | date=April 1936 | issue=3 | doi=10.1002/asna.19362580303 | bibcode=1936AN....258...39H | language=de }}</ref>
<ref name=Hoffmeister_1957>{{citation | postscript=. | title=On Two Abnormal Stars of Delta Cephei Type | last=Hoffmeister | first=Cuno | journal=Astrophysical Journal | volume=125 | page=824 | date=May 1957 | doi=10.1086/146358 | bibcode=1957ApJ...125..824H }}</ref>
<ref name=Lloyd_Evans_et_al_1972>{{citation | postscript=. | title=V553 Centauri: a type II cepheid with an overabundance of carbon | display-authors=1 | last1=Lloyd Evans | first1=T. | last2=Wisse | first2=P. N. J. | last3=Wisse | first3=M. | journal=Monthly Notices of the Royal Astronomical Society | volume=159 | page=67 | year=1972 | doi=10.1093/mnras/159.1.67 | doi-access=free | bibcode=1972MNRAS.159...67L }}</ref>
<ref name=Cotrell_1979>{{citation | postscript=. | title=Carbon and nitrogen abundances in the carbon-rich Cepheid V553 Centauri | last=Cotrell | first=P. L. | journal=Monthly Notices of the Royal Astronomical Society | volume=189 | pages=13–25 | date=October 1979 | doi=10.1093/mnras/189.1.13 | doi-access=free | bibcode=1979MNRAS.189...13C }}</ref>
<ref name=Petersen_1981>{{citation | postscript=. | title=V553 Centauri and a progression of bumps in BL Herculis light curves | last=Petersen | first=J. O. | journal=Astronomy and Astrophysics | volume=96 | pages=146–150| date=March 1981 | bibcode=1981A&A....96..146P }}</ref>
<ref name=Wallerstein_Gonzalez_1998>{{citation | postscript=. | title=V553 Cen and the Carbon Cepheids | last1=Wallerstein | first1=G. | last2=Gonzalez | first2=G. | work=A Half Century of Stellar Pulsation Interpretation: A Tribute to Arthur N. Cox; proceedings of a Conference held in Los Alamos, NM 16-20 June 1997 | editor1-first=Paul A. | editor1-last=Bradley | editor2-first=Joyce A. | editor2-last=Guzik | series=ASP Conference Series | volume=135 | page=36 | year=1998 | bibcode=1998ASPC..135...36W }}</ref>
<ref name=Wallerstein_Gonzalez_1996>{{citation | postscript=. | title=The carbon Cepheid V553 Cen: evidence of triple-alpha and CNO cycling | last1=Wallerstein | first1=George | last2=Gonzalez | first2=Guillermo | journal=Monthly Notices of the Royal Astronomical Society | volume=282 | issue=4 | pages=1236–1246 | date=October 1996 | doi=10.1093/mnras/282.4.1236 | doi-access=free | bibcode=1996MNRAS.282.1236W }}</ref>
</references>
==Further reading== {{Div col|small=yes}} *{{citation | postscript=. | title=Spectroscopy of Selected Pulsating Stars: the Anomalous Variable V351 CEP | last1=Galazutdinov | first1=G. A. | last2=Klochkova | first2=V. G. | journal=Astronomical and Astrophysical Transactions | volume=8 | issue=3 | pages=227–237 | year=1995 | doi=10.1080/10556799508203309 | bibcode=1995A&AT....8..227G }} *{{citation | postscript=. | display-authors=1 | title=The chemical composition and luminosity of the CH-type cepheid, V553 Centauri | last1=Wallerstein | first1=G. | author1-link=George Wallerstein | last2=Brown | first2=J. A. | last3=Bates | first3=B. A. | journal=Publications of the Astronomical Society of the Pacific | volume=91 | pages=47–52 | date=February 1979 | doi=10.1086/130438 | bibcode=1979PASP...91...47W }} *{{citation | postscript=. | title=UBVRI photometry of V553 Centauri | last=Landolt | first=A. U. | journal=Publications of the Astronomical Society of the Pacific | volume=87 | pages=373–377 | date=June 1975 | doi=10.1086/129777 | bibcode=1975PASP...87..373L }} *{{citation | postscript=. | title=Some Observations of the Anomalous Cepheid V553 Centauri | last1=Wisse | first1=P. N. J. | last2=Wisse | first2=M. | journal=Monthly Notes of the Astronomical Society of Southern Africa | volume=29 | page=151 | year=1970 | bibcode=1970MNSSA..29..151W }} {{Div col end}}
{{Centaurus}}
<!-- Properties --> [[Category:BL Herculis variables]] [[Category:G-type giants]] <!-- Location/catalogues --> [[Category:Centaurus]] [[Category:Durchmusterung objects|CD−31 11449]] [[Category:Henry Draper Catalogue objects|129981]] [[Category:Hipparcos objects|072257]] [[Category:Objects with variable star designations|Centauri, V553]] [[Category:Population I stars]]