View source for HX Velorum

{{Short description|Variable star in the constellation Vela}}
{{Starbox begin
| name= HX Velorum
}}
{{Starbox image
| image = [[Image:HXVelLightCurve.png|250px]]
| caption = A [[light curve]] for HX Velorum, plotted from ''[[Transiting Exoplanet Survey Satellite|TESS]]'' data.<ref name=MAST/>
}}
{{Starbox observe
| epoch=J2000
| ra={{RA|08|42|16.19252}}<ref name=dr3/>
| dec={{DEC|-48|05|56.7481}}<ref name=dr3/>
| appmag_v= 5.48 - 5.53<ref name=gcvs/>
| constell=[[Vela (constellation)|Vela]] }}
{{Starbox character
| class = B1.5V<ref name="Blackford2019"/>
| b-v = −0.17<ref name="Blackford2019"/>
| u-b = −0.9<ref name="Blackford2019"/>
| variable = [[Rotating ellipsoidal variable|ELL]]<ref name=gcvs/>
}}
{{Starbox astrometry
| radial_v = {{val|42.0|4.5}}<ref name="Gontcharov2006"/>
| prop_mo_ra = {{val|-3.714|0.128}}<ref name=dr3/>
| prop_mo_dec = {{val|4.758|0.138}}<ref name=dr3/>
| parallax = 0.9479
| p_error = 0.1121
| parallax_footnote = <ref name=dr3/>
| absmag_v = −2.32<ref name=melnik2020/>
}}<!--
{{Starbox orbit
| reference = 
| primary = 
| name = 
| period = 
| period_unitless = 
| axis = 
| axis_unitless = 
| eccentricity = 
| inclination = 
| node = 
| periastron = 
| periarg = 
| periarg_primary = 
| k1 =
| k2 = 
}}-->
{{Starbox detail
| source                 = <ref name="Blackford2019"/>
| component1             = Aa
| mass                   = {{val|8.5|1.7}}
| radius                 = {{val|5.0|0.3}}
| temperature            = {{val|fmt=commas|25,000|1300}}
| luminosity             = {{val|fmt=commas|8700|1500}}
| component2             = Ab
| mass2                  = {{val|5.4|1.2}}
| radius2                = {{val|3.1|0.3}}
| temperature2           = {{val|fmt=commas|20,000|2500}}
| luminosity2            = {{val|fmt=commas|1400|800}}
}}
{{Starbox catalog
 | names = [[Henry Draper Catalogue|HD]]&nbsp;74455, [[Star catalogue#BS, BSC, HR|HR]]&nbsp;3462, [[Hipparcos catalogue|HIP]]&nbsp;42712, [[Star catalogue#SAO|SAO]]&nbsp;220313<ref name=SIMBAD/>
}}
{{Starbox reference |
  Simbad=HX+Vel
}}
{{Starbox end}}

'''HX Velorum''', also known as '''HR 3462''' and '''HD 74455''', is a star in the constellation [[Vela (constellation)|Vela]]. It is a 5th [[apparent magnitude|magnitude]] star, so it will be faintly visible to the [[naked eye]] of an observer far from [[light pollution|city lights]]. It is a [[variable star]], whose brightness varies slightly from [[apparent magnitude|magnitude]] 5.48 to 5.53 over a period of 1.12 days.<ref name=gcvs/>

In 1981, Robert Shobbrook announced that HR 3462 is a variable star based on observations made in 1976. He correctly classified it as an [[ellipsoidal variable]], but the period he derived, {{val|fmt=commas|0.56205|0.00005}} days, was a factor of two too short because his data did not allow him to distinguish between primary and secondary minima in the [[light curve]].<ref name="Shobbrook1981"/> It was given the [[variable star designation]] HX Velorum in 1980.<ref name="Kholopov1981"/> In 1983, Christoffel Waelkens and Frédy Rufener published the correct period of variability, 1.124 days.<ref name="Waelkens1983"/>

HX Velorum is a [[triple star]], consisting of a pair (components A, magnitude 5.5, and B, magnitude 8.28) separated by 0.5 [[Minute and second of arc|arc seconds]]. Component A is itself a close binary pair (components Aa and Ab).<ref name="WDS"/><ref name="Blackford2019"/> The system's brightness variation is caused by the [[Ellipsoid|ellipsoidal]] Aa and Ab components orbiting each other.<ref name="Blackford2019"/>

HX Velorum is only about 2 [[Minute and second of arc|arc minutes]] from the center of [[IC 2395]], so it appears to be within that cluster. However the ''[[Gaia (spacecraft)|Gaia]]'' DR3 dataset lists the parallax of HX Velorum as {{val|0.9479|0.1121|ul=mas}}, yielding a distance of {{val|fmt=commas|3400|500|300}} [[light year]]s, while the distance to IC 2395 has been estimated to be {{val|fmt=commas|4560|200}}<ref name="Jaehnig2021"/> light years, so HX Velorum might be a foreground object rather than a true cluster member. Mark Blackford ''et al.'' concluded HX Velorum is a member of the cluster, but that conclusion was based in part on earlier, significantly different distance estimates for both the star and the cluster.<ref name="Blackford2019"/>

==References==
{{reflist |refs=

<ref name=melnik2020>{{cite journal |bibcode=2020Ap&SS.365..112M |title=Distance scale for high-luminosity stars in OB associations and in field with Gaia DR2. Spurious systematic motions |last1=Melnik |first1=A. M. |last2=Dambis |first2=A. K. |journal=Astrophysics and Space Science |year=2020 |volume=365 |issue=7 |page=112 |doi=10.1007/s10509-020-03827-0 |arxiv=2006.14649 |s2cid=220128144 }}</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=19 March 2023}}</ref>

<ref name=dr3>{{cite Gaia DR3|5329122067149201152}}</ref>

<ref name=gcvs>{{cite journal
 | bibcode=2017ARep...61...80S
 | title=General catalogue of variable stars: Version GCVS 5.1
 | 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.
 | journal=Astronomy Reports | year=2017 | volume=61 | issue=1 | page=80
 | doi=10.1134/S1063772917010085 | s2cid=125853869 | doi-access=free }}</ref>

<ref name=SIMBAD>{{cite simbad
 | title= V* HX Vel -- Double or Multiple Star | access-date=2023-03-18}}</ref>

<ref name="Blackford2019">{{cite journal
 | last1=Blackford | first1=M. G. | last2=Erdem | first2=A. | last3=Sürgit | first3=D.
 | last4=Özkardeş | first4=B. | last5=Budding | first5=E. | last6=Butland | first6=R.
 | last7=Demircan | first7=O.
 | title=Absolute parameters of young stars: HX Velorum
 | journal=Monthly Notices of the Royal Astronomical Society
 | date=July 2019 | volume=487 | issue=1 | pages=161–167
 | doi=10.1093/mnras/stz1136 | bibcode=2019MNRAS.487..161B |doi-access=free }}</ref>

<ref name="Jaehnig2021">{{cite journal
 | last1=Jaehnig | first1=Karl | last2=Bird | first2=Jonathan
 | last3=Holley-Bockelmann | first3=Kelly
 | title=Membership Lists for 431 Open Clusters in Gaia DR2 Using Extreme Deconvolution Gaussian Mixture Models
 | journal=The Astrophysical Journal | date=December 2021 | volume=923 | issue=1
 | page=129 | doi=10.3847/1538-4357/ac1d51 | arxiv=2108.02783 | bibcode=2021ApJ...923..129J |doi-access=free }}</ref>

<ref name="WDS">{{cite web
 | url=http://www.astro.gsu.edu/wds/
 | website=The Washington Double Star Catalog | title=The Washington Double Star Catalog
 | publisher=Georgia State University | access-date=21 March 2023}}</ref>

<ref name="Shobbrook1981">{{cite journal
 | last1=Shobbrook | first1=R. R.
 | title=Short period variability of some early B stars
 | journal=Monthly Notices of the Royal Astronomical Society
 | date=July 1981 | volume=196 | issue=2
 | pages=129–134
 | doi=10.1093/mnras/196.2.129 | bibcode=1981MNRAS.196..129S |doi-access=free }}</ref>

<ref name="Kholopov1981">{{cite journal
 | last1=Kholopov | first1=P. N. | last2=Samus | first2=N. N.
 | last3=Kukarkina | first3=N. P. | last4=Medvedeva | first4=G. I.
 | last5=Perova | first5=N. B.
 | title=65th Name-List of Variable Stars
 | journal=Information Bulletin on Variable Stars
 | date=February 1981 | volume=1921 | page=1 | bibcode=1981IBVS.1921....1K
 | url=https://ibvs.konkoly.hu/pub/ibvs/1901/1921.pdf
 | access-date=21 March 2023}}</ref>

<ref name="Waelkens1983">{{cite journal
 | last1=Waelkens | first1=C. | last2=Rufener | first2=F.
 | title=An observational study of the influence of close companions on the pulsations of beta Cephei stars
 | journal=Astronomy and Astrophysics | date=May 1983 | volume=121 | pages=45–50
 | bibcode=1983A&A...121...45W }}</ref>

<ref name="Gontcharov2006">{{cite journal
 | last1=Gontcharov | first1=G. A.
 | title=Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system
 | journal=Astronomy Letters | date=November 2006 | volume=32 | issue=11 | pages=759–771
 | doi=10.1134/S1063773706110065 | bibcode=2006AstL...32..759G |arxiv=1606.08053 | s2cid=119231169
 }}</ref>

}}

{{Stars of Vela}}

{{DEFAULTSORT:HX Velorum}}
[[Category:Vela (constellation)]]
[[Category:Objects with variable star designations|Velorum, HX]]
[[Category:Henry Draper Catalogue objects|074455]]
[[Category:Hipparcos objects|042712]]
[[Category:Bright Star Catalogue objects|3462]]
[[Category:Rotating ellipsoidal variables]]
[[Category:B-type main-sequence stars]]