Recent ultraviolet spectra from the Hubble Space Telescope ( HST ) and Far Ultraviolet Spectroscopic Explorer ( FUSE ) satellites demonstrate that UV line and continuum fluxes observed from Mira B are increasing back towards the levels that the International Ultraviolet Explorer observed in 1979–1980 and 1990–1995 , after having been found in a very low state by HST and FUSE in 1999–2001 .
The UV emission is associated with accretion of material onto Mira B from Mira A ’ s massive wind , so the variability is presumably due to variations in accretion rate .
From wind absorption features , we estimate a Mira B mass loss rate of 2.5 \times 10 ^ { -12 } M _ { \odot } yr ^ { -1 } , indicating that Mira B ’ s wind has increased in strength along with the accretion rate .
The UV variability may be associated with a previously reported 14-year periodicity in Mira B ’ s optical emission .