EI Cancri

EI Cancri, also known as G 9-38 and GJ 1116, is a binary star system consisting of two M-type stars. Located at a distance of 16.7 light-years, it is among the nearest star systems.
This system consist of two very-low-mass stars that are orbiting each other at an assumed orbital separation of 7.0 astronomical units and an estimated period of 42 years. Component A has an apparent magnitude 13.93, 0.127 times the Sun's mass, 0.136 times the Sun's radius, and 0.14% of the Sun's luminosity. Component B has an apparent magnitude 13.75, 0.111 times the Sun's mass, 0.119 times the Sun's radius, and 0.09% of the Sun's luminosity. At the very end of the main sequence, with spectral classifications of M8Ve and M7V respectively, their effective temperatures are below. A 2015 search for a third star in the system has yielded inconclusive results.
Image:EICncLightCurve.png|thumb|left|An ultraviolet band light curve showing several flares on EI Cancri, adapted from Pettersen
In 1985, Bjørn Ragnvald Pettersen announced his discovery that the star shows very high stellar flare activity, with an average of five flares per hour. It was given its variable star designation, EI Cancri, in 1987.