re: Comets ( I'll pass on the asteroids in this reply)
Hmm, interesting, did a little more readong, apparently cyclotron radiation and synchroton radiation are basically the same (circling charge), just synchrotron radiation is from charges are near relativistic velocities. I guess maybe I just meant good ol' fashioned cyclotron type. Hehe.
IE, electrons and other charged particles circling in a self-confined magnetic field that constricts the coma cold potentially create said x-rays, yeah?
Just wondering if that's feasible.