FM4p.11 — Analysis of Co-spatial UV-Optical STIS Spectra of Six Planetary Nebulae From HST Cycle 19 GO 12600

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Aug 4th at 6:00 PM until 7:30 PM




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Author(s): Timothy Reid Miller4, Richard B. C. Henry4, Reginald J. Dufour3, Karen Kwitter6, Richard A Shaw2, Bruce Balick5, Romano Corradi1

Institution(s): 1. IAC, 2. NOAO, 3. Rice University, 4. University of Oklahoma, 5. University of Washington, 6. Williams College

We present an analysis of six spatially resolved planetary nebulae (PNe), NGC 3242, NGC 5315, NGC
5882, NGC 7662, IC 2165, and IC 3568, from observations in the Cycle 19 program GO 12600 using HST
STIS. These six observations cover the wavelength range 1150-10,270 Å with 0.2 and 0.5 arcsec wide
slits, and are co-spatial to 0.1 arcsec along a 25 arcsec length across each nebula. The wavelength and
spatial coverage enabled this detailed study of physical conditions and abundances from UV and optical
line emissions (compared to only optical lines) for these six PNe. The first UV lines of interest are those
of carbon. The resolved lines of C III] 1906.68 and 1908.73 yielded a direct measurement of the density
within the volume occupied by doubly-ionized carbon and other similar co-spatial ions as well as
contributed to an accurate measurement of the carbon abundance. Each PN spectrum was divided into
smaller spatial regions in order to assess inferred density variations among the regions along the entire
slit. There is a clear difference in the inferred density for several regions of each PNe. Variations in
electron temperature and chemical abundances were also probed and shown to be nearly completely
homogeneous within the errors. Lastly, these nebulae were modeled in detail with the photoionization
code CLOUDY. This modeling tested different density profiles in order to reproduce the observed density
variations and temperature fluctuations, and constrain central star parameters. We gratefully
acknowledge generous support from NASA through grants related to the Cycle 19 program GO 12600, as
well as from the University of Oklahoma.