HX Velorum, also known asHR 3462 andHD 74455, is a star in the constellationVela. It is a 5thmagnitude star, so it will be faintly visible to thenaked eye of an observer far fromcity lights. It is avariable star, whose brightness varies slightly frommagnitude 5.48 to 5.53 over a period of 1.12 days.[3]
In 1981, Robert Shobbrook announced that HR 3462 is a variable star based on observations made in 1976. He correctly classified it as anellipsoidal variable, but the period he derived,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 thelight curve.[8] It was given thevariable star designation HX Velorum in 1980.[9] In 1983, Christoffel Waelkens and Frédy Rufener published the correct period of variability, 1.124 days.[10]
HX Velorum is atriple star, consisting of a pair (components A, magnitude 5.5, and B, magnitude 8.28) separated by 0.5arc seconds. Component A is itself a close binary pair (components Aa and Ab).[11][4] The system's brightness variation is caused by theellipsoidal Aa and Ab components orbiting each other.[4]
HX Velorum is only about 2arc minutes from the center ofIC 2395, so it appears to be within that cluster. However theGaia DR3 dataset lists the parallax of HX Velorum as0.9479±0.1121 mas, yielding a distance of3,400+500 −300light years, while the distance to IC 2395 has been estimated to be4,560±200[12] light years, so HX Velorum might be a foreground object rather than a true cluster member. Mark Blackfordet 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.[4]
^Waelkens, C.; Rufener, F. (May 1983). "An observational study of the influence of close companions on the pulsations of beta Cephei stars".Astronomy and Astrophysics.121:45–50.Bibcode:1983A&A...121...45W.
