HY Velorum
# HY Velorum

HY Velorum is a binary star 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. The distance to this system, as estimated from its annual parallax shift of 7.1 mas, is 460 light years. HY Vel most likely forms a gravitationally bound pair with the magnitude 5.45 binary system KT Vel (HD 74535); both are members of the IC 2391 open cluster. As of 1998, HY Vel and KT Vel had an angular separation of 76.1″ along a position angle of 311°.

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 0.006 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, corresponding to the catalogued period of 1.55106 days. It has a stellar classification of B3 IV, matching a B-type subgiant star.

