View source for Astronomy:HD 102776

{{Short description|Binary star system in the constellation Centaurus}}
{{Starbox begin
 | name = j Centauri
}}
{{Starbox observe
 | epoch       = J2000.0
 | constell    = [[Astronomy:Centaurus|Centaurus]]
 | ra          = {{RA|11|49|41.05745}}<ref name=GaiaDR2/>
 | dec         = {{DEC|−63|47|18.4299}}<ref name=GaiaDR2/>
 | appmag_v    = 4.30<ref name=xhip/> {{nowrap|(+4.30 - 4.39)}}<ref name=vsx/>
}}
{{Starbox character
 | type        = 
 | class       = B3V<ref name=Houk1979/>
 | b-v         = −0.15
 | u-b         = −0.59
 | variable    = [[Astronomy:Gamma Cassiopeiae variable|γ Cas]]<ref name=vsx/>
}}
{{Starbox astrometry
 | radial_v    = {{val|+29.0|4.1}}<ref name=xhip/>
 | prop_mo_ra  = -20.76 ± 0.56<ref name="van Leeuwen2007"/>
 | prop_mo_dec = 4.30 ± 0.48<ref name="van Leeuwen2007"/>
 | parallax    = 5.4391
 | p_error     = 0.4369
 | parallax_footnote = <ref name=GaiaDR2/>
 | absmag_v    = −1.98<ref name=xhip/>
}}
{{Starbox detail
 | source      = 
 | mass        = {{val|5.955|u=solar mass}}<ref name=kervella2019/><br>{{val|7.2|0.1}}<ref name=Tetzlaff_et_al_2011/>
 | radius      = {{Val|5.00|0.10}}<ref name=Arcos2018/>
 | luminosity  = 1,342<ref name=xhip/>
 | temperature = {{Val|20000|200|fmt=commas}}<ref name=Arcos2018/>
 | gravity     = {{Val|3.20|0.03}}<ref name=Arcos2018/>
 | metal_fe    = 
 | rotational_velocity = {{Val|200|4}}<ref name=Arcos2018/>
 | age_myr     = {{val|31.6|0.6}}<ref name=Tetzlaff_et_al_2011/>
}}
{{Starbox catalog
 | names = {{odlist | B=j Cen | HR=4537 | HD=102776 | CP=−63°1988 | FK5=2944 | HIP=57669 | SAO=251602 | GC=16201 | NSV=5357 }}<ref name=SIMBAD/>
}}
{{Starbox reference
 | Simbad=HD+102776
}}
{{Starbox end}}

'''HD 102776''', also known by its [[Astronomy:Bayer designation|Bayer designation]] '''j Centauri''', is a suspected [[Astronomy:Astrometric binary|astrometric binary]]<ref name=Eggleton_Tokovinin_2008/> [[Astronomy:Star|star]] system in the southern [[Astronomy:Constellation|constellation]] of [[Astronomy:Centaurus|Centaurus]]. It has a blue-white hue and is faintly visible to the naked eye with a typical [[Astronomy:Apparent visual magnitude|apparent visual magnitude]] of 4.30.<ref name=xhip/> The distance to this star is approximately 600&nbsp;[[Light year|light year]]s based on [[Astronomy:Stellar parallax|parallax]], and it is drifting further away with a [[Astronomy:Radial velocity|radial velocity]] of ~29&nbsp;km/s.<ref name=xhip/> It is a member of the Lower Centaurus Crux subgroup of the Sco OB2 association.<ref name=Brown_Verschueren_1997/> HD 102776 has a relatively large [[Astronomy:Peculiar velocity|peculiar velocity]] of {{val|31.1|u=km/s}} and is a candidate [[Astronomy:Runaway star|runaway star]] that was ejected from its association, most likely by a [[Astronomy:Supernova|supernova]] explosion.<ref name=Hoogerwerf_et_al_2001/>

The [[Astronomy:Stellar classification|stellar classification]] of the visible component is B3V,<ref name=Houk1979/> matching a [[Astronomy:B-type main-sequence star|B-type main-sequence star]]. It is around 32<ref name=Tetzlaff_et_al_2011/>&nbsp;million years old and is spinning rapidly with estimates of its projected rotational velocity ranging from 200<ref name=Arcos2018/> up to {{val|270|u=km}}, giving it an [[Astronomy:Equatorial bulge|equatorial bulge]] that is up to 11% larger than the polar radius.<ref name=vanBelle2012/> This is a [[Astronomy:Be star|Be star]] showing emission features in its Balmer lines due to a circumstellar disk of decreated gas.<ref name=Arcos2017/> It is classified as a suspected [[Astronomy:Gamma Cassiopeiae variable|Gamma Cassiopeiae type]] [[Astronomy:Variable star|variable star]] with a visual magnitude varying from +4.30 down to +4.39.<ref name=vsx/>

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

<ref name=SIMBAD>{{cite simbad
 | title=j Cen | access-date=2021-01-28 }}</ref>

<ref name=GaiaDR2>{{Cite Gaia DR2|5333141671190375040}}</ref>

<ref name=Arcos2017>{{cite journal
 | title=Evidence for Different Disk Mass Distributions between Early- and Late-type Be Stars in the BeSOS Survey
 | display-authors=1 | last1=Arcos | first1=C.
 | last2=Jones | first2=C. E. | last3=Sigut | first3=T. A. A.
 | last4=Kanaan | first4=S. | last5=Curé | first5=M.
 | journal=The Astrophysical Journal
 | volume=842 | issue=1 | id=48 | pages=18 | date=June 2017
 | arxiv=1704.08133 | bibcode=2017ApJ...842...48A 
 | doi=10.3847/1538-4357/aa6f5f | s2cid=119418279 | doi-access=free }}</ref>

<ref name=Hoogerwerf_et_al_2001>{{cite journal
 | title=On the origin of the O and B-type stars with high velocities. II. Runaway stars and pulsars ejected from the nearby young stellar groups
 | display-authors=1 | last1=Hoogerwerf | first1=R.
 | last2=de Bruijne | first2=J. H. J. | last3=de Zeeuw | first3=P. T.
 | journal=Astronomy and Astrophysics
 | volume=365 | pages=49–77 | date=January 2001
 | issue=2 | arxiv=astro-ph/0010057 | bibcode=2001A&A...365...49H 
 | doi=10.1051/0004-6361:20000014 | s2cid=18970167 }}</ref>

<ref name=Tetzlaff_et_al_2011>{{cite journal
 | title=A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun
 | display-authors=1 | last1=Tetzlaff | first1=N.
 | last2=Neuhäuser | first2=R. | last3=Hohle | first3=M. M.
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=410 | issue=1 | pages=190–200 |date=January 2011
 | doi=10.1111/j.1365-2966.2010.17434.x | s2cid=118629873
 | bibcode=2011MNRAS.410..190T | arxiv=1007.4883 }}</ref>

<ref name=vanBelle2012>{{cite journal
 | last1=van Belle | first1=Gerard T.
 | title=Interferometric observations of rapidly rotating stars
 | journal=The Astronomy and Astrophysics Review
 | volume=20 | issue=1 | page=51 | date=March 2012
 | doi=10.1007/s00159-012-0051-2 | arxiv=1204.2572
 | bibcode=2012A&ARv..20...51V | s2cid=119273474 }}</ref>

<ref name=Houk1979>{{cite book
 | last1=Houk | first1=Nancy
 | title=Michigan catalogue of two-dimensional spectral types for the HD stars
 | publisher=Department of Astronomy, University of Michigan
 | location=Ann Arbor, Michigan | volume=1 | year=1979
 | bibcode=1978mcts.book.....H }}</ref>

<ref name=Eggleton_Tokovinin_2008>{{cite journal
 | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A.
 | title=A catalogue of multiplicity among bright stellar systems
 | journal=[[Organization:Monthly Notices of the Royal Astronomical Society|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 | arxiv=0806.2878
 | bibcode=2008MNRAS.389..869E | s2cid=14878976 }}</ref>

<ref name=Brown_Verschueren_1997>{{cite journal
 | title=High S/N Echelle spectroscopy in young stellar groups. II. Rotational velocities of early-type stars in SCO OB2
 | last1=Brown | first1=A. G. A. | last2=Verschueren | first2=W.
 | journal=Astronomy and Astrophysics
 | volume=319 | pages=811–838 | date=March 1997
 | arxiv=astro-ph/9608089 | bibcode=1997A&A...319..811B }}</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=57481 Vizier catalog entry ]</ref>

<ref name=Arcos2018>{{cite journal 
 | title=Stellar parameters and H α line profile variability of Be stars in the BeSOS survey
 | display-authors=1 | last1=Arcos | first1=C. | last2=Kanaan | first2=S.
 | last3=Chávez | first3=J. | last4=Vanzi | first4=L.
 | last5=Araya | first5=I. | last6=Curé | first6=M.
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=474 | issue=4 | pages=5287–5299 | date=March 2018
 | doi=10.1093/mnras/stx3075 | bibcode=2018MNRAS.474.5287A
 | arxiv=1711.08675 }}</ref>

<ref name=vsx>{{cite web
 | url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=43981
 | title=NSV 5357 | website=Variable Star Index
 | publisher=American Association of Variable Star Observers
 | access-date=2020-02-19 }}</ref>

<ref name=xhip>{{cite journal
 | title=XHIP: An extended hipparcos compilation
 | last1=Anderson | first1=E. | last2=Francis | first2=Ch.
 | 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=kervella2019>{{cite journal
 | title=Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly
 | last1=Kervella | first1=Pierre | last2=Arenou | first2=Frédéric
 | last3=Mignard | first3=François | last4=Thévenin | first4=Frédéric
 | journal=Astronomy and Astrophysics
 | volume=623 | pages=A72 | year=2019
 | bibcode=2019A&A...623A..72K | arxiv=1811.08902
 | doi=10.1051/0004-6361/201834371 | s2cid=119491061 }}</ref>

}}

{{Stars of Centaurus}}

{{DEFAULTSORT:Hd 102776}}
<!-- Properties -->
[[Category:B-type main-sequence stars]]
[[Category:Gamma Cassiopeiae variable stars]]
[[Category:Be stars]]
[[Category:Suspected variables]]
<!-- Other -->
[[Category:Bayer objects|Centauri, j]]
[[Category:Durchmusterung objects|CD-63 00674]]
[[Category:Henry Draper Catalogue objects|102776]]
[[Category:Hipparcos objects|057669]]
[[Category:Bright Star Catalogue objects|4537]]
[[Category:Lower Centaurus Crux]]

{{Sourceattribution|HD 102776}}