BY Draconis variable

Nearby K and M stars that are BY Draconis variables include Barnard's Star, Kapteyn's Star, 61 Cygni, Ross 248, Lacaille 8760, Lalande 21185, Epsilon Eridani and Luyten 726-8. Ross 248 is the first discovered BY Draconis variable, the variability having been identified by Gerald Edward Kron in 1950. The variability of BY Draconis itself was discovered in 1966 and studied in detail by Pavel Fedorovich Chugainov over the period 1973–1976.

Some of these stars may exhibit flares, resulting in additional variations of the UV Ceti type. Likewise, the spectra of BY Draconis variables (particularly in their H and K lines) are similar to RS CVn stars, which are another class of variable stars that have active chromospheres.