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   51060
   It has been long puzzling problem how the LMXB systems has been
   created. One of the key clues to answer this question can be obtained
   by measuring the metal abundance of companion star's atomosphere. In
   some models, the metal abundance depends on the origin of the binary;
   i.e. capture or binary evolution. Spectral analysis of X-ray dips
   provides a unique oppotunity to directory measure the metal abundance
   of accreting matter. For this kind of study we think X1254-690 is the
   best X-ray source. We estimat that we can constrain the abundances of
   silicon, sulphar, and iron atoms from a 40 ksec observation.
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