COSMIC-RAYS .5. THE NONTHERMAL RADIO-EMISSION OF THE OLD NOVA GK PERSEI - A SIGNATURE OF HADRONIC-INTERACTIONS

Using the model of particle acceleration in shocks in stellar winds de veloped by Biermann (1993) and Biermann & Cassinelli (1993) we demonst rate that the nonthermal radio emission spectrum from the cataclysmic variable binary star GK Per can be interpreted consistently. We propos e that the radio spectrum results from hadronic secondary electrons/po sitrons, which, in the optically thin case, give a characteristic radi o spectrum with a spectral index of +1/3 below a maximum and, for a st rong shock in a wind slow compared to the shock speed, of -0.7 above t he maximum. We test the proposed concept for consistency with the radi o data for OB and Wolf Rayet stars as well as radiosupernovae. There i s some evidence that this process is important for the radio emission from active galactic nuclei, both in compact and extended emission. We argue that such a radio spectrum is a unique characteristic for hadro nic interactions.