Lalande 21185 Exoplanet System

Three potential exoplanets around the fourth closest star // Lalande 21185, also known as Gliese 411 or HD 95735, is a real exoplanet system located 8. 30 light-years away in the constellation Ursa Major. It comes in behind Alpha Centauri, Barnard's Star, and Wolf 359 as the fourth-closest stellar system to the Sun (sixth if counting brown dwarf systems). Lalande 21185 is an 8-billion-year-old spectral type M2V red dwarf with 0. 39 solar masses, 0. 37 solar radii, and a surface temperature of 3719 K (3446 °C). Despite being close in astronomical terms, it is only around 2% of the Sun's luminosity and cannot be seen with the unaided eye. Lalande 21185 is an example of a BY Draconis variable star, meaning that its brightness changes regularly as large starspots on its surface rotate in and out of view. Despite some magnetic activity, it is generally considered fairly quiescent in terms of producing flares. Due to its proximity, Lalande 21185 has long been the subject of various astronomical surveys, but it wasn't until 2019 that an exoplanet was robustly detected. It was confirmed the following year. Designated Lalande 21185 b, this super-Earth is, as of 2025 estimates, at least 2. 35 times the mass of our home planet with a 12. 94-day, 0. 077 AU orbit around its star. With a predicted equilibrium temperature of 370 K (97 °C), it lies interior to the habitable zone and is most likely too hot to support liquid water on its surface. A second planet, Lalande 21185 c, was proposed in 2021 and confirmed in 2022. It is located at a distance of 2. 77 AU from its star and takes 2801 days (7. 67 years) to complete one orbit. If placed in the solar system, it would sit about halfway between Mars and Jupiter. The estimated minimum mass of Lalande 21185 c has undergone several revisions, with the newest data in 2025 indicating 18. 7 Earth masses. Since its host star is much cooler and dimmer than the Sun, Lalande 21185 c orbits at a distance equivalent to that of the Solar System's ice gi