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   PR # 12143
    We propose three 20 ksec ASCA observations of the accreting X-ray
    pulsar GS 0834-430 at different orbital phases.  BATSE's continuous
    all-sky coverage will provide simultaneous observations if the source
    is in outburst. BATSE's detection of outbursts at various phases of
    the newly measured 111 day orbit has raised new questions about the
    type of stellar companion and the mass transfer mechanism. The small
    eccentricity (less than 0.07) implies that tidal dissipation has circ
    ularized the orbit, which is only possible if the companion is, or
    once was, a red giant. In addition to accurate timing and pulse-phase
    spectroscopy, ASCA's measurement of $N_H$ and the fluorescent iron
    line at different orbital phases will help unravel this still myster-
   ious source.
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