Mu Velorum (μ Vel, μ Velorum) is a

binary star A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in wh ...

system in the southern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Vela. The two stars orbit each other with a

semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the long ...

of 1.437

arcsecond A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...

s and a period of 116.24 years. ( Wulff-Dieter Heintz (1986) lists a period of 138 years with his orbital elements.) The pair have a combined apparent visual magnitude of 2.69, making the system readily visible to the naked eye. From

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

measurements, the distance to this system is estimated to be . 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 In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

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 The Extreme Ultraviolet Explorer (EUVE or Explorer 67) was a NASA space telescope for ultraviolet astronomy. EUVE was a part of NASA's Explorer spacecraft series. Launched on 7 June 1992. With instruments for ultraviolet (UV) radiation between ...

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 In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

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 A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors i ...

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.

References

{{DEFAULTSORT:Mu Velorum Velorum, Mu Vela (constellation) Binary stars G-type giants G-type main-sequence stars 4216 093497 052727 Durchmusterung objects