Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pointing Chandra Toward the Extreme Ultraviolet Fluxes of Very Low-Mass
  Stars   The X-ray and EUV emission of stars plays a key role in the loss and
evolution of the atmospheres of their planets. The coronae of dwarf stars later
than M6 appear to behave differently to those of earlier spectral types and are
more X-ray dim and radio bright. Too faint to have been observed by the Extreme
Ultraviolet Explorer, their EUV behavior is currently highly uncertain. We have
devised a method to use the Chandra X-ray Observatory High Resolution Camera to
provide a measure of EUV emission in the 50-170 \AA\ range and have applied it
to the M6.5 dwarf LHS 248 in a pilot 10 ks exposure. Analysis with model
spectra using simple, idealised coronal emission measure distributions inspired
by an analysis of Chandra HETG spectra of the M5.5 dwarf Proxima Cen and
results from the literature, finds greatest consistency with a very shallow
emission measure distribution slope, $DEM \propto T^{3/2}$ or shallower, in the
range $\log T=5.5$-$6.5$. Within $2\sigma$ confidence, a much wider range of
slopes can be accommodated. Model spectra constrained by this method can
provide accurate (within a factor of 2-4) synthesis and extrapolation of EUV
spectra for wavelengths $<400$-500 \AA. At longer wavelengths models are
uncertain by an order of magnitude or more, and depend on the details of the
emission measure distribution at temperatures $\log T < 5.5$. The method is
sensitive to possible incompleteness of plasma radiative loss models in the 30
170 \AA\ range for which re-examination would be warranted.

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The categories of this paper are: solv-int
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The categories of this paper are: cs
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: econ
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The categories of this paper are: eess
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
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The categories of this paper are: atom-ph