Guardians of the Stars
Groombridge 1618 is a star in the constellation Ursa Major. It is located close to Earth, at a distance of less than 16 light years. It is an orange dwarf star of spectral type K8 V.
Groombridge 1618 has a stellar classification of K8 V, which means it is a K-type main sequence star that is generating energy by fusing hydrogen at its core. It has 67% of the mass of the Sun, 61% of the Sun’s radius, but radiates only 4.6% of the Sun’s energy. The effective surface temperature of the star’s photosphere is about 4,000 K, giving it an orange hue.
It is a BY Draconis variable with a surface magnetic field strength of 750 G. The chromosphere is relatively inactive and possesses star spots comparable to Sun spots. However, like the star UV Ceti, it has been observed to undergo increases in luminosity as a flare star. It has a greater luminosity than most flare stars, which are typically red dwarfs, but is less active. The level of activity suggests that this is a somewhat youthful star.
Groombridge 1618 does possess a low temperature debris disk. Consisting of a ring of coarse highly-reflective dust at a temperature below 22 K orbiting at least 51 AU from the host star.