*************************************************************************
   73007
   We have discovered a 13s periodic signal in the X-ray flux emitted by
   HD49798, an hydrogen depleted subdwarf O6 spectroscopic binary with an
   orbital period of 1.55d. This revealed that the unseen companion is an
   accreting degenerate star. It is unclear yet whether this is a white
   dwarf or a neutron star. In either case HD49798 represents an
   evolutionary stage that had not been observed before. We propose a
   single 30ks ASCA observation of this unique source aimed at obtaining
   an additional accurate period measurement and to look for orbital
   signatures (dips, smooth flux variation, Doppler shift) expected for
   such low-mass X-ray binary system.
 *************************************************************************