{{Short description|Star in the constellation Centaurus}} {{about-distinguish|A Centauri|Alpha Centauri{{!}}α Centauri|HD 125823{{!}}a Centauri|Centaurus A}} {{Starbox begin}} {{Starbox image | image= {{Location mark |image=Centaurus constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=A Centauri |x=882|y=784 }} |caption=Location of A Centauri (circled) }} {{Starbox observe | epoch = J2000.0 | constell = [[Centaurus]]<ref name=Anderson2012/> | ra = {{RA|11|34|45.66}}<ref name="van Leeuwen2007"/> | dec = {{DEC|−54|15|50.7}}<ref name="van Leeuwen2007"/> | appmag_v = +4.62<ref name=Anderson2012/> }} {{Starbox character | type = [[Main sequence]]<ref name=Zorec2012/> | class = B9V<ref name=Houk1979/> | b-v = −0.08<ref name=johnson1966/> | u-b = −0.21<ref name=johnson1966/> | variable = }} {{Starbox astrometry | radial_v = {{Val|+5.7|2.2}}<ref name=Anderson2012/> | prop_mo_ra = {{Val|-56.17|0.18}}<ref name="van Leeuwen2007"/> | prop_mo_dec = {{Val|16.19|0.20}}<ref name="van Leeuwen2007"/> | parallax = 7.65 | p_error = 0.22 | parallax_footnote = <ref name="van Leeuwen2007"/> | absmag_v = −0.96<ref name=Anderson2012/> }} {{Starbox detail | source = | mass = {{Val|3.58|0.05}}<ref name=Zorec2012/> | radius = 4.7<ref name=tic/> | luminosity = 306<ref name=Zorec2012/> | temperature = 10,600<ref name=Zorec2012/> | gravity = 3.54<ref name=tic/> | metal_fe = 0.50<ref name=cardiel2021/> | rotation = 0.733<ref name=balona2021/> days | rotational_velocity = 160<ref name=Zorec2012/> | age_myr = 238<ref name=gontcharov2012/> }} {{Starbox catalog | names = {{odlist | B=A Cen | CP=−53°4637 | FK5=2926 | HD=100673 | HIP=56480 | HR=4460 | SAO=239189 | GC=15877 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = A+Cen }} {{Starbox end}}
'''HD 100673''', also known as '''A Centauri''' is a single<ref name=Eggleton2008/> [[star]] in the [[southern celestial hemisphere|southern]] [[constellation]] of [[Centaurus]]. It is blue-white in hue and is faintly visible to the naked eye with an [[apparent visual magnitude]] of +4.62.<ref name=Anderson2012/> The star is located at a distance of approximately 430 [[light-year]]s from the [[Sun]] based on [[stellar parallax]].<ref name="van Leeuwen2007"/> It appears to be drifting further away with a [[radial velocity]] of around +6 km/s.<ref name=Anderson2012/>
This is a rapidly rotating [[Be star]], showing an [[emission-line]] [[stellar spectrum|spectrum]] on top of the normal [[Spectral line|absorption]] spectrum of the star, due to a [[circumstellar disk]] of ejected matter. It doesn't show any absorption lines from the disk.<ref name=hanuschik1996/> It is a [[B-type main-sequence star]] with a [[stellar classification]] of B9V.<ref name=Houk1979/>
== References == {{Reflist|refs=
<ref name=SIMBAD>{{cite simbad | title=A Cen | access-date=2020-02-27 }}</ref>
<ref name=tic>{{cite journal |bibcode=2019AJ....158..138S |title=The Revised TESS Input Catalog and Candidate Target List |last1=Stassun |first1=Keivan G. |last2=Oelkers |first2=Ryan J. |last3=Paegert |first3=Martin |last4=Torres |first4=Guillermo |last5=Pepper |first5=Joshua |last6=De Lee |first6=Nathan |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. |journal=The Astronomical Journal |date=2019 |volume=158 |issue=4 |page=138 |doi=10.3847/1538-3881/ab3467 |doi-access=free |arxiv=1905.10694 |display-authors=1 }}</ref>
<ref name=balona2021>{{cite journal |bibcode=2021ApJ...921....5B |title=TESS Observations of be Stars: General Characteristics and the Impulsive Magnetic Rotator Model |last1=Balona |first1=Luis A. |last2=Ozuyar |first2=Dogus |journal=The Astrophysical Journal |date=2021 |volume=921 |issue=1 |page=5 |doi=10.3847/1538-4357/ac1a77 |doi-access=free |arxiv=2008.06288 }}</ref>
<ref name=johnson1966>{{cite journal |bibcode=1966CoLPL...4...99J |title=UBVRIJKL Photometry of the Bright Stars |last1=Johnson |first1=H. L. |last2=Mitchell |first2=R. I. |last3=Iriarte |first3=B. |last4=Wisniewski |first4=W. Z. |journal=Communications of the Lunar and Planetary Laboratory |date=1966 |volume=4 |page=99 }}</ref>
<ref name=cardiel2021>{{cite journal |bibcode=2021MNRAS.504.3730C |title=Synthetic RGB photometry of bright stars: Definition of the standard photometric system and UCM library of spectrophotometric spectra |last1=Cardiel |first1=Nicolás |last2=Zamorano |first2=Jaime |last3=Bará |first3=Salvador |last4=Sánchez De Miguel |first4=Alejandro |last5=Cabello |first5=Cristina |last6=Gallego |first6=Jesús |last7=García |first7=Lucía |last8=González |first8=Rafael |last9=Izquierdo |first9=Jaime |last10=Pascual |first10=Sergio |last11=Robles |first11=José |last12=Sánchez |first12=Ainhoa |last13=Tapia |first13=Carlos |journal=Monthly Notices of the Royal Astronomical Society |date=2021 |volume=504 |issue=3 |page=3730 |doi=10.1093/mnras/stab997 |doi-access=free |arxiv=2103.17009 }}</ref>
<ref name=gontcharov2012>{{cite journal |bibcode=2012AstL...38..771G |title=Dependence of kinematics on the age of stars in the solar neighborhood |last1=Gontcharov |first1=G. A. |journal=Astronomy Letters |date=2012 |volume=38 |issue=12 |page=771 |doi=10.1134/S1063773712120031 |arxiv=1606.08814 }}</ref>
<ref name="van Leeuwen2007">{{cite journal | title=Validation of the new Hipparcos reduction | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | year=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 }} [http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=I/311/hip2&recno=56297 Vizier catalog entry ]</ref>
<ref name=Anderson2012>{{cite journal | 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 | doi=10.1134/S1063773712050015 | s2cid=119257644 }}</ref>
<ref name=Zorec2012>{{cite journal | last1=Zorec | first1=J. | last2=Royer | first2=F. | title=Rotational velocities of A-type stars. IV. Evolution of rotational velocities | journal=Astronomy & Astrophysics | volume=537 | page=A120 | date=January 2012 | bibcode=2012A&A...537A.120Z | arxiv=1201.2052 | doi=10.1051/0004-6361/201117691 | s2cid=55586789 }}</ref>
<ref name=Eggleton2008>{{cite journal | 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 }}</ref>
<ref name=Houk1979>{{cite book | last1=Houk | first1=Nancy | last2=Cowley | first2=A. P. | title=Michigan catalogue of two-dimensional spectral types for the HD stars | location=Ann Arbor, Michigan | publisher=Department of Astronomy, University of Michigan | volume=1 | year=1979 | bibcode=1978mcts.book.....H }}</ref>
<ref name=hanuschik1996>{{cite journal |bibcode=1996A&A...308..170H |title=On the structure of be star disks |last1=Hanuschik |first1=R. W. |journal=Astronomy and Astrophysics |volume=308 |pages=170 |year=1996 }}</ref>
}}
== External links == *Wikisky [http://www.wikisky.org/?ra=11.579349499999998&de=-54.26409000000002&zoom=8&show_grid=1&show_constellation_lines=1&show_constellation_boundaries=1&show_const_names=0&show_galaxies=1&show_box=1&box_ra=11.5793495&box_de=-54.26409&box_width=50&box_height=50&img_source=DSS2 image] of HD 100673 (A Centauri)
{{Stars of Centaurus}}
[[Category:B-type main-sequence stars]] [[Category:Be stars]] [[Category:Centaurus]] [[Category:Bayer objects|Centauri, A]] [[Category:Durchmusterung objects|PD-53 4637]] [[Category:Henry Draper Catalogue objects|100673]] [[Category:Hipparcos objects|056480]] [[Category:Bright Star Catalogue objects|4460]]