SIMBAD references

We present a photometric study of the compact HII region Sh2-88B and its associated stellar cluster. The positions and JHKmagnitudes are obtained for 125 stars over an 80''x80'' field centered on the region. The region has two components, called Sh2-88B1 and Sh2-88B2. B1 is a compact cometary HII region associated with a cluster containing several massive stars. The dominant exciting star, at the center of the cometary structure, has an ionizing radiation flux corresponding to a spectral type in the range O8.5V-O9.5V. It is highly reddened, with a visual extinction in the 30-42mag range, and exhibits a near-IR excess. B1 has a simple morphology, with the ionized and neutral gas clearly separated. Its unidentified infrared band (UIB) emission, observed by ISOCAM in the 5-8.5 µm passband, comes from the photodissociation region at the periphery of the ionized gas. B2 is an ultracompact HII region whose exciting star, probably of spectral type later than B0.5V, is not detected; this indicates a visual extinction greater than 60mag. A very steep and regular increase of the extinction from west to east is observed over the whole of Sh2-88B.