{{Short description|Star in the constellation Vela}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=O Velorum Cluster iTelescope.png|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=20|mark_link=HY Velorum |x=675|y=832 }} | caption = Location of HY Velorum in IC 2391 (circled in red; north is to the left) }} {{Starbox observe | epoch = J2000 | constell = Vela | ra = {{RA|08|42|25.38667}}<ref name=GaiaDR2/> | dec = {{DEC|-53|06|50.3324}}<ref name=GaiaDR2/> | appmag_v = 4.81 - 4.86<ref name=gcvs/> }} {{Starbox character | type = | class = B3&nbsp;IV<ref name=houk1978/> | b-v = {{Val|−0.173|0.007}}<ref name=Anderson2012/> | u-b = | variable = SPB<ref name=gcvs/> }} {{Starbox astrometry | radial_v = {{Val|+15.6|0.2}}<ref name=Anderson2012/> | prop_mo_ra = −24.83<ref name=vanLeeuwen2007/> | prop_mo_dec = +23.21<ref name=vanLeeuwen2007/> | parallax = 7.1141 | p_error = 0.2302 | parallax_footnote = <ref name=GaiaDR2/> | absmag_v = −1.25<ref name=Anderson2012/> }} {{Starbox orbit | reference = <ref name=DeCat2000/> | period_unitless = {{Val|8.378|0.001|u=day}} | eccentricity = {{Val|0.24|0.04}} | periastron = {{nowrap|2450741.3 ± 0.2 HJD}} | periarg = {{Val|93|9}} | k1 = {{Val|8.0|0.3}} }} {{Starbox detail | source = | component1 = HY Vel Aa | mass = 5.4<ref name=Szewczuk2015/> | radius = | luminosity = {{Val|830|927|743}}<ref name=Szewczuk2015/> | gravity = 4.07<ref name=Niemczura2003/> | temperature = {{Val|16865|235|231|fmt=commas}}<ref name=Szewczuk2015/> | metal_fe = {{Val|0.03|0.02}}<ref name=Niemczura2003/> | rotational_velocity = 45<ref name=Szewczuk2015/> | age_myr = 179<ref name=Gontcharov2012/> }} {{Starbox catalog | names={{odlist | V=HY Vel | CPD=−52°1607 | HD=74560 | HIP=42726 | HR=3467 | SAO=236205 | WDS=J08424-5307A }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = HD+74560 }} {{Starbox end}}

'''HY Velorum''' is a binary star<ref name=DeCat2000/> system in the southern constellation of Vela. It is a dim star but visible to the naked eye with an apparent visual magnitude of 4.83.<ref name=Anderson2012/> The distance to this system, as estimated from its annual parallax shift of {{Val|7.1|ul=mas}},<ref name=GaiaDR2/> is 460&nbsp;light years. HY Vel most likely forms a gravitationally bound pair with the magnitude 5.45 binary system KT Vel (HD 74535);<ref name=Eggleton2008/> both are members of the IC 2391 open cluster.<ref name=Dodd2007/> As of 1998, HY Vel and KT Vel had an angular separation of {{Val|76.1|ul=arcsecond}} along a position angle of 311°.<ref name=WDSC2014/>

[[File:HYVelLightCurve.png|thumb|left|A visual band light curve for HY Velorum, adapted from Waelkens and Rufener (1985)<ref name="Waelkens"/>]] This is a single-lined spectroscopic binary system with an orbital period of 8.4&nbsp;days and an eccentricity of 0.24. The visible component has an ''a'' sin ''i'' value of {{Val|0.006|ul=AU}}, where ''a'' is the semimajor axis and ''i'' is the (unknown) orbital inclination to the line of sight.

In 1979, Shyam M. Jakate announced the discovery that the star's brightness varies.<ref name="Jakate1979"/> It was given its variable star designation, HY Velorum, in 1981.<ref name="Kholopov1981"/> The primary, which is the variable star, is a slowly pulsating B-type star having at least three pulsational modes, with the dominant mode showing a frequency of 0.64472 cycles per day,<ref name=DeCat2000/> corresponding to the catalogued period of 1.55106 days.<ref name=gcvs/> It has a stellar classification of B3&nbsp;IV, matching a B-type subgiant star.<ref name=houk1978/>

{{clear left}} ==References== <references>

<ref name="Waelkens">{{cite journal |last1=Waelkens |first1=C. |last2=Rufener |first2=F. |title=Photometric variability of mid-B stars |journal=Astronomy and Astrophysics |date=November 1985 |volume=152 |pages=6–14 |bibcode=1985A&A...152....6W |url=https://ui.adsabs.harvard.edu/abs/1985A&A...152....6W |access-date=30 April 2022}}</ref>

<ref name=SIMBAD>{{cite simbad | title=HD 74560 | access-date=16 August 2018 }}</ref>

<ref name=GaiaDR2>{{Cite Gaia DR2|5318486456796462848}}</ref>

<ref name=houk1978>{{citation | last1=Houk | first1=Nancy | title=Michigan catalogue of two-dimensional spectral types for the HD stars | volume=2 | location=Ann Arbor | publisher=Dept. of Astronomy, University of Michigan | year=1978 | bibcode=1978mcts.book.....H | postscript=. }}</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=23 December 2024}}</ref>

<ref name=vanLeeuwen2007>{{citation | first1=F. | last1=van Leeuwen | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=November 2007 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | arxiv=0708.1752 | s2cid=18759600 | postscript=. }}</ref>

<ref name="Jakate1979">{{cite journal | last1=Jakate | first1=S. M. | title=A search for Beta Cephei stars. III. Photometric studies of southern B-type stars | journal=Astronomical Journal | date=April 1979 | volume=84 | pages=552–558 | doi=10.1086/112448 | bibcode=1979AJ.....84..552J | url=https://articles.adsabs.harvard.edu/pdf/1979AJ.....84..552J | access-date=23 December 2024}}</ref>

<ref name=Dodd2007>{{citation | contribution=Unified Absolute Spectrophotometry for Star Clusters | last1=Dodd | first1=R. J. | title=The Future of Photometric, Spectrophotometric and Polarimetric Standardization. Proceedings of a conference held 8-11 May, 2006 in Blankenberge, Belgium | series=ASP Conference Series | editor1-first=C. | editor1-last=Sterken | location=San Francisco | publisher=Astronomical Society of the Pacific | volume=364 | page=237 | date=April 2007 | bibcode=2007ASPC..364..237D | postscript=. }}</ref>

<ref name=Eggleton2008>{{citation | title=A catalogue of multiplicity among bright stellar systems | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | journal=Monthly Notices of the Royal Astronomical Society | volume=389 | issue=2 | pages=869 | date=2008 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | arxiv=0806.2878 | bibcode=2008MNRAS.389..869E | s2cid=14878976 | postscript=. }}</ref>

<ref name=WDSC2014>{{citation | display-authors=1 | last1=Mason | first1=B. D. | last2=Wycoff | first2=G. L. | last3=Hartkopf | first3=W. I. | last4=Douglass | first4=G. G. | last5=Worley | first5=C. E. | title=The Washington Visual Double Star Catalog | journal=The Astronomical Journal | year=2014 | volume=122 | issue=6 | pages=3466–3471 | bibcode=2001AJ....122.3466M | doi=10.1086/323920 | doi-access=free }}</ref>

<ref name=DeCat2000>{{citation | title=A study of bright southern slowly pulsating B stars. I. Determination of the orbital parameters and of the main frequency of the spectroscopic binaries | last1=De Cat | first1=P. | last2=Aerts | first2=C. | last3=De Ridder | first3=J. | last4=Kolenberg | first4=K. | last5=Meeus | first5=G. | last6=Decin | first6=L. | journal=Astronomy and Astrophysics | volume=355 | pages=1015–1030 | date=2000 | bibcode=2000A&A...355.1015D | postscript=. }}</ref>

<ref name=Szewczuk2015>{{citation | title=Identification of pulsational modes in rotating slowly pulsating B-type stars | last1=Szewczuk | first1=W. | last2=Daszyńska-Daszkiewicz | first2=J. | journal=Monthly Notices of the Royal Astronomical Society | volume=450 | issue=2 | pages=1585–1603 | date=June 2015 | doi=10.1093/mnras/stv715 | doi-access=free | bibcode=2015MNRAS.450.1585S | arxiv=1504.04490 | s2cid=119194953 | postscript=. }}</ref>

<ref name=Gontcharov2012>{{citation | title=Spatial distribution and kinematics of OB stars | last1=Gontcharov | first1=G. A. | journal=Astronomy Letters | volume=38 | issue=11 | pages=694–706 | date=November 2012 | doi=10.1134/S1063773712110035 | bibcode=2012AstL...38..694G | arxiv=1606.09028 | s2cid=119108982 | postscript=. }}</ref>

<ref name=Niemczura2003>{{citation | last1=Niemczura | first1=E. | postscript=. | title=Metallicities of the SPB stars from the IUE ultraviolet spectra | journal=Astronomy and Astrophysics | volume=404 | issue=2 | pages=689–700 | date=June 2003 | doi=10.1051/0004-6361:20030546 | bibcode=2003A&A...404..689N | doi-access=free }}</ref>

<ref name=Anderson2012>{{citation | 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 | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | s2cid=119257644 | postscript=. }}</ref>

<ref name=gcvs>{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}</ref>

</references>

{{Stars of Vela}}

Category:B-type subgiants Category:Slowly pulsating B-type stars Category:Vela (constellation) 074560 042726 3467 Velorum, HY Category:Spectroscopic binaries PD-52 01607