086444

We have been studying for years two symbiotic binaries in the Small Magellanic Cloud that host nuclear burning white dwarfs. They belong to a group of observed symbiotics that may represent only the d_commatip of the icebergd_comma of a large class of such binaries hosting massive white dwarfs with shell nuclear burning. They constitute primary candidate for type Ia supernovae from single degenerate systems comma or may instead evolve to d_commadouble degeneratesd_comma. The supersoft X-rays are the only window to observing nuclear burning directly comma and long term monitoring is necessary to assess the parameters to evaluate the evolution of these binaries.