The two stars orbit each other with an period of 138 years and a very high eccentricity of 0.94. Their semi-major axis is of 50 astronomical units,[a] 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.[b] The system is about 360 million years old.[3]
The primary component is a giant star with an apparent magnitude of 2.7 and a stellar classification of G5 III.[3] It is radiating about 107 times the luminosity of the Sun from an expanded atmosphere about 13 times the Sun's radius.[8] The mass of this star is 3.3 times that of the Sun.[7] 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 1.7 × 1030 erg s−1.[3]
The fainter companion, Mu Velorum B, is a main sequence star with an apparent magnitude of 6.4[3] and an assigned stellar classification of G2V.[3] 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.[3]
Notes
^ abCalculated from angular semi-major axis of 1.40″±0.17″[6] and distance of 35.9 parsecs.[1]
^ abcdJohnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
^ abcdefghijklmAyres, Thomas R.; Osten, Rachel A.; Brown, Alexander (November 1999), "The Rise and Fall of μ Velorum: A Remarkable Flare on a Yellow Giant Star Observed with the Extreme Ultraviolet Explorer", The Astrophysical Journal, 526 (1): 445–450, Bibcode:1999ApJ...526..445A, doi:10.1086/308001, S2CID120689663.
^Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
^ abIzmailov, Igor; Khovritchev, Maxim (January 2025), "New Orbital Parameters of 850 Wide Visual Binary Stars and Their Statistical Properties", Research in Astronomy and Astrophysics, 25 (1): 015016, Bibcode:2025RAA....25a5016I, doi:10.1088/1674-4527/ad9da3, ISSN1674-4527.
