Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: H I Free-Bound Emission of Planetary Nebulae with Large Abundance
  Discrepancies: Two-Component Models versus Kappa-distributed electrons   The "abundance discrepancy" problem in the study of planetary nebulae (PNe),
viz., the problem concerning systematically higher heavy-element abundances
derived from optical recombination lines relative to those from collisionally
excited lines, has been under discussion for decades, but no consensus on its
solution has yet been reached. In this paper we investigate the hydrogen
free-bound emission near the Balmer jump region of four PNe that are among
those with the largest abundance discrepancies, aiming to examine two recently
proposed solutions to this problem: two-component models and Kappa electron
energy distributions. We find that the Balmer jump intensities and the spectrum
slopes cannot be simultaneously matched by the theoretical calculations based
upon single Maxwell-Boltzmann electron-energy distributions, whereas the
fitting can be equally improved by introducing Kappa electron energy
distributions or an additional Maxwell-Boltzmann component. We show that
although H I free-bound emission alone cannot distinguish the two scenarios, it
can provide important constraints on the electron energy distributions,
especially for cold and low-Kappa plasmas.

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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-fin
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The categories of this paper are: q-alg
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: comp-gas