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   PR # 42042
   The discovery of numerous Super Soft Sources (SSS) by ROSAT has
   confirmed that SSS are a new, important category of astronomical
   objects. Their nature is unclear, mainly because spectral information
   obtained by ROSAT is very limited. In our recent ASCA observation of
   the SSS RXJ0925.7-4758, which is effectively the first X-ray
   spectroscopy of SSS, we clearly detected absorption edge structures
   from highly ionized heavy elements, indicating the emission is from
   hot and optically thick white dwarf or neutron star atmosphere. We
   propose to carry out a similar spectral study of CAL87, which is a
   prototype of SSS and the only other SSS observable with ASCA. The
   ASCA high resolution spectra will be crucial in modeling the X-ray
   emission from SSS.
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