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   61109
   In order to estimate correct total mass of a binary system of galaxies,
   we sugget to adopt mass determination method based on X-ray observation
   of hot gas associated with the system; such method is much more
   reliable than traditional one which is based on velocity difference and
   apparent separation between member galaxies of the system, if dark halo
   extends over orbit of the members. We propose an ASCA 100 ksec
   observation of a binary system of galaxies NGC 7679/NGC 7682 to explore
   such dark halo enveloping the entire system.
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