A&A 434, 1077-1084 (2005)
DOI: 10.1051/0004-6361:20042116
Seismology of triple-mode classical Cepheids of the Large Magellanic Cloud
P. Moskalik1 and W. A. Dziembowski2, 11 Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warsaw, Poland
e-mail: pam@camk.edu.pl
2 Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warsaw, Poland
(Received 5 October 2004/ Accepted 23 December 2004)
Abstract
We interpret the three periods detected in OGLE
LMC
Cepheids
SC3-360128
and
SC5-338399
as corresponding to the first three overtones
of radial pulsations. This interpretation imposes stringent
constraints on parameters of the stars and on their evolutionary
status, which could only be the first crossing of the instability
strip. Evolutionary models reproducing measured periods exist only
in a restricted range of metallicities (
Z=0.004 - 0.007). The
models impose an upper limit to the extent of overshooting from
the convective core. Absolute magnitude of each star is confined
to a narrow interval, which allows us to derive a new estimate of
the distance to the
LMC
. We obtain the value of m-M
ranging from
to
with a systematic difference
between the two stars of about
. The rates of period
change predicted by the models are formally in conflict with the
derived observational limits, though the uncertainties of
measured
may have been underestimated. If this
discrepancy is confirmed, it would constitute a significant
challenge to the stellar evolution theory.
Key words: stars: variables: Cepheids -- stars: oscillations -- stars: evolution -- galaxies: Magellanic Clouds
SIMBAD Objects
© ESO 2005
BibSonomy
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