Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Envelope tomography of long-period variable stars II. Method   A tomographic method is described that makes it possible to follow the
propagation of shock waves across the photosphere of long-period variable
stars. The method relies on the correlation of the observed spectrum with
numerical masks probing layers of different atmospheric depths. The formation
depth of spectral lines is derived from synthetic spectra of non-variable red
giant stars. When applied to Mira stars around maximum light, the tomographic
masks reveal that the deepest photospheric layers are generally characterized
by blueshifted absorption lines (attesting their upward motion), whereas the
uppermost layers generally exhibit redshifted absorption lines (indicating
their infalling motion). Double absorption lines are found in intermediate
layers, where the shock front is located. At later phases, the shock front is
seen moving towards upper layers, until it leaves the photosphere.

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The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
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The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci