A highly variable methanol maser in G111.256-0.770

Abstract

G111.256-0.770 is a high-mass young stellar object associated with a weak 6.7 GHz methanol maser showing strong variability. We present results of a multi-epoch monitoring program of the target, conducted with the Torun 32 m telescope for more than a decade. We found that the isotropic maser luminosity varied by a factor 16 on a timescale of 5-6 yr and individual features showed small amplitude short-lived (about 0.2 yr) bursts superimposed on higher amplitude slow (>5 yr) variations.