Mu Velorum
Mu Velorum is a binary star system in the southern constellation Vela. The pair have a combined apparent visual magnitude of 2.69, making the system readily visible to the naked eye. From parallax measurements, the distance to this system is measured at.
Characteristics
The two stars orbit each other with a period of 138 years and a very high eccentricity of 0.94. Their semi-major axis is of 50 astronomical units, but due to this high eccentricity the separation at periastron is just 3.1 au, while at the apoastron their separation is about 100 au. The system is about 360 million years old.The primary component is a giant star with an apparent magnitude of 2.7 and a stellar classification of G5 III. It is radiating about 107 times the luminosity of the Sun from an expanded atmosphere about 13 times the Sun's radius. The mass of this star is 3.3 times that of the Sun. In 1998, the Extreme Ultraviolet Explorer space telescope detected a strong flare that released an X-ray emission nearly equal to the output of the entire star. The quiescent X-ray luminosity of Mu Velorum A is about.
The fainter companion, Mu Velorum B, is a main sequence star with an apparent magnitude of 6.4 and an assigned stellar classification of G2V. However, this classification is suspect. Closer examination of the spectrum suggests the star may actually have a classification of F4V or F5V, which suggests a mass of about 1.5 times the mass of the Sun. Such stars typically do not show a marked level of magnetic activity.