I was wondering whether thermonuclear fusion could be achieved in accretion disks around black holes, or even neutron stars/white dwarfs. Seems like, in AGN at the very least, you would easily get the kind of temperatures and pressures necessary for thermonuclear fusion, perhaps even synthesis of heavier elements (above Iron). I have never heard of this, but I would be a little surprised if it weren't true. Does anyone know if this is supposed to happen, or do we have any sort of direct spectroscopic evidence supporting it? I would be interested to know. Thanks!