THE CASE OF NGC 6302: THE IMPACT OF SHOCKS IN THE DERIVATION OF NITROGEN ABUNDANCES
P. J. A. Lago, R. D. D. Costa, M. Faúndez-Abans, W. J. Maciel
Monthly Notices Roy. Astron. Soc. in press (2019)
High nitrogen abundance is characteristic of Type I planetary nebulae as
well as their highly lamentary structure. In the present work we test the
hypothesis of shocks as a relevant excitation mechanism for a Type-I nebula,
NGC 6302, using recently released diagnostic diagrams to distinguish shocks
from photoexcitation. The construction of diagrams depends on emission line
ratios and kinematical information. NGC 6302 shows the relevance of shocks
in peripheral regions and the importance to the whole nebula. Using shocks,
we question the usual assumption of ICF calculation, justifying a warning to
broadly used abundance derivation methods. From a kinematical analysis, we
derive a new distance for NGC 6302 of 805 143 pc.
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