ROSAT HRI X-ray observations of the open globular cluster NGC 288

A ROSAT HRI X-ray image was obtained of the open globular cluster NGC 288, which is located near the South Galactic Pole. This is the first deep X-ray image of this system. We detect a low-luminosity globular cluster X-ray so urce (LLGCX) RX J005245.0-263449 with an X-ray luminosity of (5.5 +/- 1.4) x 10(32) ergs s(-1) (0.1-2.0 keV), which is located very close to the clust er center. There is evidence for X-ray variability on a timescale of less t han or similar to 1 day. The presence of this LLGCX in such an open globula r cluster suggests that dense stellar systems with high interaction rates a re not needed to form LLGCXs. We also searched for diffuse X-ray emission f rom NGC 288. Upper limits on the X-ray luminosities are L-X(h) < 9.5 x 10(3 2) ergs s(-1) (0.52-2.02 keV) and L-X(s) < 9.3 x 10(32) ergs s(-1) (0.11-0. 41 keV), These imply upper limits to the diffuse X-ray-to-optical light rat ios in NGC 288, which are lower than the values observed for X-ray faint ea rly-type galaxies. This indicates that the soft X-ray emission in these gal axies is due either to a component that is not present in globular clusters (e.g., interstellar gas or a stellar component that is not found in low-me tallicity Population II systems) or to a relatively small number of bright low-mass X-ray binaries.