{{Short description|Star in the constellation Centaurus}} {{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=HD 105382 |x=800|y=670 }} | caption = Location of HD 105382 (invisible beside [[δ Centauri]] at this scale) }} {{starbox observe | epoch=J2000 | constell=[[Centaurus]] | ra= {{RA|12|08|05.22401}}<ref name=vanLeeuwen2007/> | dec= {{DEC|-50|39|40.5728}}<ref name=vanLeeuwen2007/> | appmag_v=4.47<ref name=SIMBAD>{{cite simbad|title=HD 105382|access-date=25 October 2017}}</ref> |names= }} {{starbox character | class= B6III<ref name=Petit2013/> | b-v = −0.15<ref name=SIMBAD/> | u-b = −0.67<ref name=SIMBAD/> | variable = rotating variable<ref name=Briquet2004/> }} {{starbox astrometry | radial_v=16.5<ref name=SIMBAD/> | prop_mo_ra=−35.16<ref name=vanLeeuwen2007/> | prop_mo_dec=−6.47<ref name=vanLeeuwen2007/> | parallax=7.44 | p_error=0.61 | parallax_footnote = <ref name=vanLeeuwen2007/> | absmag_v = {{Val|−1.2|0.3}}<ref name=Petit2013/> | absmag_bol = −2.9 ± 0.4<ref name=Petit2013/> }} {{Starbox detail | source = | mass = 5.7 ± 0.4<ref name=Briquet2004/> | radius = 3.0 ± 0.6<ref name=Briquet2004/> | luminosity = 1000{{±|590|370}}<ref name=Petit2013/> | temperature = 17400 ± 400<ref name=Briquet2004/> | gravity = 4.18 ± 0.15<ref name=Briquet2004/> | metal_fe = | rotational_velocity = 90<ref name=Petit2013/> | rotation = 1.295 ± 0.001<ref name=Briquet2004/> days | age_myr = }} {{starbox catalog | names={{odlist|CD=−49°6813|HD=105382|HIP=59173|HR=4618|SAO=239687}}<ref name=SIMBAD/> }}{{Starbox reference | Simbad = HD+105382 }}{{starbox end}}
'''HD 105382''' (also known as '''V863 Centauri''') is a [[star]] in the [[constellation]] [[Centaurus (constellation)|Centaurus]]. Its [[apparent magnitude]] is 4.47, making it visible to the [[naked eye]] under good observing conditions. From [[parallax]] measurements, it is located 130 [[parsecs]] (440 [[light year]]s) from the Sun.
[[File:V863CenLightCurve.png|thumb|left|250px|A [[light curve]] for V863 Centauri, plotted from ''[[Hipparcos]]'' data<ref name=HipDataAccess/>]]
In 1992, Luis A. Balona ''et al.'' announced their discovery that HD 105382 is a [[variable star]].<ref name="Balona1992"/> It was given its [[variable star designation]], V863 Centauri, in 1993.<ref name="Kazarovets1993"/> HD 105382's apparent magnitude varies with an amplitude of 0.012 over a period of 1.295 days. It has been previously classified as a [[Be star]], which would explain the variability as stellar pulsations, but this classification was probably due to accidental observation of the nearby Be star [[δ Centauri]].<ref name=Briquet2001/> A 2004 study showed that the 1.295 day period is actually the [[stellar rotation|rotation]] period of the star, and that the variability is caused by non-homogeneous distribution of elements in the stellar surface. In particular, HD 105382 is a helium-weak [[chemically peculiar star]] with a helium abundance varying between 0.5% and 15% of the solar abundance, and a silicon abundance varying between 0.00044% and 0.0069% the solar value. Regions with more helium appear to coincide with the regions with less silicon, and vice versa.<ref name=Briquet2004/> This peculiar abundance pattern is probably related to HD 105382's [[stellar magnetic field|magnetic field]],<ref name=Briquet2004/> which has a polar strength of 2.3 [[gauss (unit)|kG]].<ref name=Petit2013/>
From [[Astrometry|astrometric]] measurements by the [[Hipparcos]] spacecraft, HD 105382 is identified as a probable [[astrometric binary]].<ref name=Makarov2005/> It is only 267" away from δ Centauri, and both stars appear to be at the same distance from Earth and have the same motion through space, so they may be related. In total, this may be a five star system.<ref name=Eggleton2008/> It is a member of the Lower Centaurus–Crux (LCC) subgroup of the [[Scorpius–Centaurus association]].<ref name=deGeus1989/>
==References== <references> <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 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 | postscript=. }}</ref>
<ref name="Kazarovets1993">{{cite journal | last1=Kazarovets | first1=E. V. | last2=Samus | first2=N. N. | last3=Goranskij | first3=V. P. | title=The 71st Name-List of Variable Stars | journal=Information Bulletin on Variable Stars | date=February 1993 | volume=3840 | pages=1-27 | bibcode=1993IBVS.3840....1K | url=https://ibvs.konkoly.hu/pub/ibvs/3801/3840.pdf | access-date=20 January 2025}}</ref>
<ref name="Balona1992">{{cite journal | last1=Balona | first1=L. A. | last2=Cuypers | first2=J. | last3=Marang | first3=F. | title=Intensive photometry of southern Be variables. II. Summer objects | journal=Astronomy and Astrophysics, Suppl. Ser. | bibcode=1992A&AS...92..533B | date=February 1992 | volume=92 | pages=533-563 | url=https://articles.adsabs.harvard.edu/pdf/1992A%26AS...92..533B | access-date=20 January 2025}}</ref>
<ref name=Petit2013>{{citation | title=A magnetic confinement versus rotation classification of massive-star magnetospheres | display-authors=1 | last1=Petit | first1=V. | last2=Owocki | first2=S. P. | last3=Wade | first3=G. A. | last4=Cohen | first4=D. H. | last5=Sundqvist | first5=J. O. | last6=Gagné | first6=M. | last7=Maíz Apellániz | first7=J. | last8=Oksala | first8=M. E. | last9=Bohlender | first9=D. A. | last10=Rivinius | first10=T. | last11=Henrichs | first11=H. F. | last12=Alecian | first12=E. | last13=Townsend | first13=R. H. D. | last14=ud-Doula | first14=A. | last15=MiMeS Collaboration | journal=Monthly Notices of the Royal Astronomical Society | volume=429 | issue=1 | pages=398–422 | date=February 2013 | doi=10.1093/mnras/sts344 | doi-access=free | bibcode=2013MNRAS.429..398P | arxiv=1211.0282 | s2cid=14961579 | 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=Briquet2001>{{cite journal |author1=Briquet, M.|author2=Aerts, C.|author3=De Cat, P. |title=Optical variability of the B-type star HD 105382: Pulsation or rotation? |journal=Astronomy and Astrophysics|volume=366|pages=121–128 |date=January 2001|bibcode=2001A&A...366..121B|doi=10.1051/0004-6361:20000193|doi-access=free}}</ref>
<ref name=Briquet2004>{{cite journal |author=Briquet, M.|display-authors=etal |title=He and Si surface inhomogeneities of four Bp variable stars |journal=Astronomy and Astrophysics|volume=413|pages=273–283 |date=January 2004|bibcode=2004A&A...413..273B|doi=10.1051/0004-6361:20031450|doi-access=free}}</ref>
<ref name=vanLeeuwen2007>{{citation | title=Validation of the new Hipparcos reduction | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 | postscript=. }}</ref>
<ref name=Makarov2005>{{citation | last1=Makarov | first1=V. V. | last2=Kaplan | first2=G. H. | title=Statistical Constraints for Astrometric Binaries with Nonlinear Motion | journal=The Astronomical Journal | postscript=. | volume=129 | issue=5 | pages=2420–2427 | date=May 2005 | doi=10.1086/429590 | bibcode=2005AJ....129.2420M | doi-access=free }}</ref>
<ref name=deGeus1989>{{citation | last1=de Geus | first1=E. J. | last2=de Zeeuw | first2=P. T. | last3=Lub | first3=J. | title=Physical parameters of stars in the Scorpio-Centaurus OB association | journal=Astronomy and Astrophysics | volume=216 | issue=1–2 | pages=44–61 |date=June 1989 | bibcode=1989A&A...216...44D }}</ref> </references>
{{Stars of Centaurus}}
[[Category:Centaurus]] [[Category:B-type giants]] [[Category:Variable stars]] [[Category:Objects with variable star designations|Centauri, V863]] [[Category:Durchmusterung objects|CD-49 06813]] [[Category:Henry Draper Catalogue objects|105382]] [[Category:Hipparcos objects|059173]] [[Category:Bright Star Catalogue objects|4618]] [[Category:Helium-weak stars]] [[Category:Astrometric binaries]] [[Category:Lower Centaurus Crux]]