83 Leonis, abbreviated83 Leo, is abinary star system approximately 59light-years away in theconstellation ofLeo (theLion). The primary star of the system is a coolorange subgiantstar, while the secondary star is anorange dwarf star. The two stars are separated by at least 515astronomical units from each other, and have a combined apparent magnitude of 6.12. Both stars are presumed to be cooler than theSun.
The primary star is also known as HD 99491 and the secondary star as HD 99492. In 2005, anexoplanet was confirmed to be orbiting the secondary star within the system.[15]
The primary component, 83 Leonis A, is a 6thmagnitude star. It is not visible to the unaided eye, but easily visible with smallbinoculars. The star is classified as asubgiant, meaning that it has ceased fusinghydrogen in its core and started toevolve towardsred gianthood.
The secondary component, 83 Leonis B, is an 8th magnitude orange dwarf, somewhat less massive (0.88 MSun), smaller and cooler than the Sun.[16] It is visible only with binoculars or better equipment. Components A and B share commonproper motion, which confirms them as a physical pair. Theprojected separation between the stars is 515 AU, but the true separation may be much higher.[17]
There is yet another, magnitude 14.4 component listed in theWashington Double Star Catalog. However, this star is moving into a different direction and is therefore not a true member of the 83 Leonis system.
In 2010, a second planet, 83 Leonis Bc, was claimed,[7] but was found to be a false positive in 2016.[4] However, in 2023 a different second planet was discovered, also given the designation "c".[13]
^abJohnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars".Communications of the Lunar and Planetary Laboratory.4: 99.Bibcode:1966CoLPL...4...99J.
