MS 1603.6+2600 is a high-latitude X-ray binary with a 111 min orbital period , thought to be either an unusual cataclysmic variable or an unusual low-mass X-ray binary .
In an ASCA observation in 1997 August , we find a burst , whose light curve suggests a Type I ( thermonuclear flash ) origin .
We also find an orbital X-ray modulation in MS 1603.6+2600 , which is likely to be periodic dips , presumably due to azimuthal structure in the accretion disk .
Both are consistent with this system being a normal low-mass X-ray binary harboring a neutron star , but at a great distance .
We tentatively suggest that MS 1603.6+2600 is located in the outer halo of the Milky Way , perhaps associated with the globular cluster Palomar 14 , 11 ^ { \circ } away from MS 1603.6+2600 on the sky at an estimated distance of 73.8 kpc .