Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The MUSCLES Treasury Survey IV: Scaling Relations for Ultraviolet, Ca II
  K, and Energetic Particle Fluxes from M Dwarfs   Characterizing the UV spectral energy distribution (SED) of an exoplanet host
star is critically important for assessing its planet's potential habitability,
particularly for M dwarfs as they are prime targets for current and near-term
exoplanet characterization efforts and atmospheric models predict that their UV
radiation can produce photochemistry on habitable zone planets different than
on Earth. To derive ground-based proxies for UV emission for use when Hubble
Space Telescope observations are unavailable, we have assembled a sample of
fifteen early-to-mid M dwarfs observed by Hubble, and compared their
non-simultaneous UV and optical spectra. We find that the equivalent width of
the chromospheric Ca II K line at 3933 Angstroms, when corrected for spectral
type, can be used to estimate the stellar surface flux in ultraviolet emission
lines, including H I Lyman alpha. In addition, we address another potential
driver of habitability: energetic particle fluxes associated with flares. We
present a new technique for estimating soft X-ray and >10 MeV proton flux
during far-UV emission line flares (Si IV and He II) by assuming solar-like
energy partitions. We analyze several flares from the M4 dwarf GJ 876 observed
with Hubble and Chandra as part of the MUSCLES Treasury Survey and find that
habitable zone planets orbiting GJ 876 are impacted by large Carrington-like
flares with peak soft X-ray fluxes >1e-3 W m-2 and possible proton fluxes
~100-1000 pfu, approximately four orders of magnitude more frequently than
modern-day Earth.

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The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: solv-int
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The categories of this paper are: cmp-lg
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The categories of this paper are: bayes-an
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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: nucl-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: atom-ph
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The categories of this paper are: nlin
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: q-fin
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The categories of this paper are: physics