Analysis of Co-spatial UV-optical HST STIS Spectra of Planetary Nebula NGC 3242

This project sought to consider two important aspects of the planetary nebulaNGC 3242 using new long-slit HST/STIS spectra. First, we investigated whether this object is chemically homogeneous by dividing the slit into different regions spatially and calculating the abundances of each region. The major result is that the elements of He, C, O, and Ne are chemically homogeneous within uncertain-ties across the regions probed, implying that the stellar outflow was well-mixed. Second, we constrained the stellar properties using photoionization models computed by CLOUDY and tested the effects of three different density profiles on these parameters. The three profiles tested were a constant density profile, aGaussian density profile, and a Gaussian with a power law density profile. The temperature and luminosity were not affected significantly by the choice of density structure. The values for the stellar temperature and luminosity from our best fit model are 89.7+7.3−4.7kK and log(L/L⊙)=3.36+0.28−0.22, respectively. Comparing to evolutionary models on an HR diagram, this corresponds to an initial and final mass of 0.95+0.35−0.09M⊙and 0.56+0.01−0.01M⊙, respectively.

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OBJ OBJ datastream 589.11 KiB application/pdf 2020-06-15
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