66 Leonis
star in the constellation Leo
66 Leonis is a single, white-hued star in the constellation of Leo. With an apparent magnitude of +6.80, it is far too faint to be viewed to the naked eye under normal conditions, and can only be faintly seen in ideal conditions under dark skies. Based on parallax measurements by the Gaia spacecraft, it lies at a distance of 271 light-years (83.1 parsecs). It is moving away from the Sun at a velocity of 12.8 km/s.
The star has a stellar classification of A5V, with the luminosity class V indicating that it is in the main sequence. It is estimated to be 100 million years old, has 1.9 times the mass of the Sun, 1.65 times the Sun's radius, and 10.5 times the Sun's luminosity. The effective temperature is 8,090 K, giving it the typical white hue of an A-type star.
Planetary system
66 Leonis hosts a super-Jupiter exoplanet, discovered combining direct imaging from the CHARIS instrument at the Subaru Telescope and astrometry data from the Hipparcos and Gaia spacecraft. Its discovery was published in 2025, making it the third planet to have been discovered using both direct imaging and astrometry, after AF Leporis b and HIP 99770 b.
The planet has an estimated radius of 1.1 RJ and an effective temperature of 2,348±218 K. It takes around 90 years to complete an orbit around 66 Leonis and has a semi-major axis of 25 astronomical units, similar to the distance of Neptune to the Sun (30.1 au).
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This entry incorporates text from “66 Leonis” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.