  If a supermassive black hole resides in the centers of galaxies, there are
several effects expected to be observed. It is likely that accretion disks are
around the supermassive black hole. Stellar interactions with the accretion
flows around the supermassive black hole play a role in that an flying-by star
may cool a hot accretion disk as a result of Comptonization. It is shown that
the Comptonization of the stellar emission will take place in a hot accretion
disk such as the ADAFs around the supermassive black hole and become a
relatively important source of the accretion disk cooling when the mass
accretion rate is low, and stars are passing outer parts of the hot accretion
disk. We suggest that such a stellar cooling can be observed in the radio
frequency regime since synchrotron luminosity of the ADAFs depends strongly on
the electron temperature and occurs much more frequently than a tidal
disruption event.
