Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Can microlensing fold caustics reveal a second stellar limb-darkening
  coefficient?   Dense high-precision photometry of microlensed stars during a fold-caustic
passage can be used to reveal their intensity profiles from which the
temperature of the stellar atmosphere as function of fractional radius can be
derived. While the capabilities of current microlensing follow-up campaigns
such as PLANET allow a precise measurement of linear limb-darkening
coefficients, the residual signal of a second coefficient characterizing
square-root limb darkening is ~ 25 times smaller which prevents a proper
determination except for unlikely cases of very high caustic-peak-to-outside
relative magnifications with no adequate event being observed so far or for
source stars passing over a cusp singularity. Although the presence of limb
darkening can be well established from the data, a reliable measurement of the
index of an underlying power-law cannot be obtained.

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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: cs
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The categories of this paper are: eess
2
The categories of this paper are: math
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: mtrl-th