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   51021
   The metal abundance of stars and SNRs derived from ASCA observation is
   generally smaller than the so-called "cosmic abundance". We are trying
   to study this mysterious problem. On early type stars, a simple
   analysis of ASCA data, assuming a thin thermal plasma model, leads to a
   poor metal abundance. However, if resonance scattering makes the
   effective optical depth for the absorption sufficiently large, ASCA
   data are consistent with the "cosmic abundance". This assumption is
   based on the three O-stars data by ASCA, whose abundances derived by
   the simple analysis are surprisingly similar. This arguments on the
   resonance scattering should be confirmed by more samples of early type
   stars.
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