UIT Observations of Open and Globular Clusters

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Session 20 -- Astro 2
Display presentation, Tuesday, June 13, 1995, 9:20am - 6:30pm

[20.12] UIT Observations of Open and Globular Clusters

R.Parise (CSC/GSFC/LASP), T.P.Stecher (NASA/GSFC/LASP), and the UIT Team

We present initial results on open and globular clusters from images obtained with the Ultraviolet Imaging Telescope (UIT) during the Astro-2 Spacelab mission March 2-18, 1995. The UIT images are recorded on image-intensified film, and have a $40'$ diameter field with a spatial resolution of $3''$. Most of the clusters were observed with an anti-dayglow filtered centered at 1620 \AA\, but a few were observed with a broader-band filter centered at 1520 \AA. Ultraviolet images of globular clusters suppress the dominant cool stellar population, and allow analysis of the radial distribution and temperature morphology of the hot horizontal branch stars. In the open clusters, ultraviolet imagery can be used to detect hot sources which are optically hidden in binary systems.

The globular clusters imaged with UIT are 47 Tuc, M3, M4, M12, M13, M92, NGC 6397, NGC 6723, NGC 6752 and Omg Cen. We have identified 369 hot horizontal branch stars in a preliminary analysis of the NGC 2808 image. The open clusters imaged with UIT are M67, NGC 188, NGC 752, NGC 3532, NGC 6791, and NGC 7789.

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