Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A first-overtone RR Lyrae star with cyclic period changes   A detailed light curve analysis is presented for a first-overtone RR Lyrae
star, MACHO* J050918.712-695015.31, based on MACHO and OGLE-III observations.
As a foreground object of the Large Magellanic Cloud, it gives an extraordinary
opportunity to study an almost continuous, 12-year long dataset of a relatively
bright (V~15.0 mag) RRc star with rapid period change. Cyclic period modulation
is suggested by the O-C method, where the cycle length is about 8 years. With
the available unique dataset, we could draw strong limits on other light curve
changes that may be associated to the period modulation. We could exclude both
multiple periodicity and amplitude modulation unambiguously. Any theoretical
model should reproduce the observed lack of photometric modulations. Simple
arguments are also given for possible hydromagnetic effects.

33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph