The binary companion to the peculiar F supergiant HD 172481 is shown to be a Mira variable with a pulsation period of 312 days .
Its characteristics are within the normal range found for solitary Miras of that period , although its pulsation amplitude and mass-loss rate \dot { M } \sim 3 \times 10 ^ { -6 } M _ { \odot } yr ^ { -1 } are higher than average .
Reasons are given for suspecting that the F supergiant , which has L \sim 10 ^ { 4 } L _ { \odot } , is a white dwarf burning hydrogen accreted from its companion .