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Session 40 - The Environment of Stars: From Protostars to the Main Sequence.
Display session, Tuesday, June 11
We present information about the stellar population in the line-of-sight to the Collinder 232 cluster located in the Great Carina Nebula. This region was observed serendipitously by the WFPC2 of the Hubble Space Telescope during a program (GO-6042) of spectroscopy of the outer condensations of Eta Carinae. Paired exposures were taken through each of the three wide-band filters: F336W, F439W, and F555W. These were combined to remove cosmic rays, hot pixels, etc. and mosaiced to produce deep UBV images of this region which reach a limiting magnitude of V\sim25 at \sim0.1^'' spatial resolution. Images were also acquired using several interference filters isolating prominent nebular emission lines.
The stellar population characteristics are discussed from color-magnitude (CMD) and color-color (CCD) diagrams for the stars over an 160'' wide L- shaped field covering the NE part of the brightest stars in Cr 232 (located some 8' north of Eta Carinae). Using the diagrams, we discuss the fraction of stars that might be members of the cluster, the magnitude and variation of reddening for the cluster stars, and estimate a distance for the cluster. These results are compared to CMD's for the rich nearby clusters Trumpler 14 (for which Cr 232 may just be an extension of) and Trumpler 16.
Finally, other aspects of star-formation evident in this field are discussed based on the emission-line images. Of particular note are several stellar [NII]-emitting knots located in many of the small dark globules previously reported by Dufour et al. (1996 BAAS, 27, 114) from these data.
This research was supported in part by grants from AURA/STScI related to the Cycle 5 HST General Observer program GO-6042.
Program listing for Tuesday