Far Ultraviolet Imaging of NGC 1783 with WFPC2

Session 61 - New Views of the Magellanic Clouds.
Display session, Wednesday, June 12
Great Hall,

[61.01] Far Ultraviolet Imaging of NGC 1783 with WFPC2

A. A. Cole, J. S. Gallagher III (U. Wisconsin, Madison), W. Freedman, R. Phelps (Carnegie Observatories)

We have imaged the intermediate-age red LMC globular cluster NGC 1783 in two ultraviolet filters with the Hubble Space Telescope's WFPC2. In order to investigate the hot component of an aging stellar population, we observed the cluster at 1600 ÅF160BW) and at 3300 ÅF336W). The resulting color-magnitude diagram picks out blue straggler candidates and one or more possible post-AGB stars. We were surprised to discover a population of hot stars lying well above the cluster turnoff at effective temperatures of 10,000 to 30,000 K. Some of the implications of this anomalous hot star population for population synthesis efforts are briefly discussed.

Program listing for Wednesday