}}{{Starbox reference
| Simbad = HD+74560
}}{{Starbox end}}HY Velorum is a binary star[12] 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.[5] The distance to this system, as estimated from its annual parallax shift of {{Val|7.1|ul=mas}},[1] is 460 light years. HY Vel most likely forms a gravitationally bound pair with the magnitude 5.45 binary system KT Vel (HD 74535);[24] both are members of the IC 2391 open cluster.[25] As of 1998, HY Vel and KT Vel had an angular separation of {{Val|76.1|ul=arcsecond}} along a position angle of 311°.[26]This is a single-lined spectroscopic binary system with an orbital period of 8.4 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.
The primary 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,[12] corresponding to the catalogued period of 1.55106 days.[3] It has a stellar classification of B3 IV, matching a B-type subgiant star.[4]
References
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7. ^1 2 3 {{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=. }}
8. ^1 2 3 4 {{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 | bibcode=2015MNRAS.450.1585S | arxiv=1504.04490 | postscript=. }}
9. ^1 {{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 | postscript=. }}
10. ^1 2 {{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 }}
11. ^1 2 3 4 {{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 | postscript=. }}
12. ^1 2 3 {{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|author1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}