Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nebular Models of Sub-Chandrasekhar Mass Type Ia Supernovae: Clues to
  the Origin of Ca-rich Transients   We use non-local thermal equilibrium radiative transport modeling to examine
observational signatures of sub-Chandrasekhar mass double detonation explosions
in the nebular phase. Results range from spectra that look like typical and
subluminous Type Ia supernovae (SNe) for higher mass progenitors to spectra
that look like Ca-rich transients for lower mass progenitors. This ignition
mechanism produces an inherent relationship between emission features and the
progenitor mass as the ratio of the nebular [Ca II]/[Fe III] emission lines
increases with decreasing white dwarf mass. Examining the [Ca II]/[Fe III]
nebular line ratio in a sample of observed SNe we find further evidence for the
two distinct classes of SNe Ia identified in Polin et al. by their relationship
between Si II velocity and B-band magnitude, both at time of peak brightness.
This suggests that SNe Ia arise from more than one progenitor channel, and
provides an empirical method for classifying events based on their physical
origin. Furthermore, we provide insight to the mysterious origin of Ca-rich
transients. Low-mass double detonation models with only a small mass fraction
of Ca (1%) produce nebular spectra that cool primarily through forbidden [Ca
II] emission.

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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: gr-qc
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The categories of this paper are: q-alg
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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: math
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: cs
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The categories of this paper are: econ