Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Rate of Period Change as a Diagnostic of Cepheid Properties   Rate of period change $\dot{P}$ for a Cepheid is shown to be a parameter that
is capable of indicating the instability strip crossing mode for individual
objects, and, in conjunction with light amplitude, likely location within the
instability strip. Observed rates of period change in over 200 Milky Way
Cepheids are demonstrated to be in general agreement with predictions from
stellar evolutionary models, although the sample also displays features that
are inconsistent with some published models and indicative of the importance of
additional factors not fully incorporated in models to date.

26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
25
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
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th