Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observational studies of Cepheid amplitudes. II Metallicity dependence
  of pulsation amplitudes   Physical and phenomenological properties (radius, luminosity, shape of the
light curve, etc.) of Cepheids strongly depend on the pulsation period, with
the exception of the pulsation amplitude. A possible factor causing a wide
range of pulsation amplitudes might be the different atmospheric metallicities
of individual Cepheids.
  We studied the influence exerted by the atmospheric iron content, [Fe/H], on
the pulsational amplitude of Galactic Cepheids. We searched for correlations
between the [Fe/H] value and both the observed amplitudes and amplitude related
parameters.
  The amplitude of the Cepheid pulsation slightly decreases with increasing
iron abundance. This effect is more pronounced for the radial velocity
variations and for the shorter pulsation periods. The wavelength dependence of
photometric amplitudes is also found to be sensitive to the metallicity. Some
of these effects are not consequences of differential line blanketing. Based on
the calibrations of the metallicity sensitivity relationships, we derived
photometric iron abundance for 21 Galactic Cepheids. The dichotomic behaviour
dividing Galactic Cepheids that pulsate in the fundamental mode into short- and
long-period groups at the period of 10.47 d can be noticed in some diagrams
that show metallicity-related dependences.
  We confirm that variety in atmospheric metallicity in Cepheids contributes to
the finite range of pulsation amplitudes at a given period. Effects of
metallicity on the amplitudes revealed from observational data and the
occurrence of the dichotomy also derived from phenomenological data have to be
confirmed by appropriate theoretical models of stellar structure and pulsation.

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The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
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The categories of this paper are: dg-ga
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The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: stat
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The categories of this paper are: solv-int
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
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The categories of this paper are: supr-con