Issue |
A&A
Volume 373, Number 1, July I 2001
|
|
---|---|---|
Page(s) | 164 - 172 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20010553 | |
Published online | 15 July 2001 |
Cepheid mass-luminosity relations from the Magellanic Clouds
1
Institut d'Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France
2
Department of Physics, University of Florida, Gainesville, Fl 32611, USA
3
Konkoly Observatory, POB 67, Budapest, 1525 Hungary
Corresponding author: J. P. Beaulieu, beaulieu@iap.fr
Received:
24
October
2000
Accepted:
5
March
2001
The OGLE data base is used in conjunction with Kurucz atmosphere
models to generate sets of period, effective temperature and
luminosity for fundamental and overtone Magellanic Cloud Cepheids.
The Florida pulsation code (with linear turbulent convection) is
then used to compute masses for these stars, assuming an average
composition of (,
) for the LMC and of (
,
) for the SMC. The average M-L relation for the
fundamental Cepheids matches closely that for the first overtone
Cepheids for each Magellanic Cloud. Neither the SMC nor the
LMC average
-
relations are straight, but have a
noticeable curvature.
In view of the uncertainties in distance and reddening we have
adopted three different choices for these quantities. The results
based on the "long" distance scale to the clouds give a better
agreement between theory and and observations than the "short" one.
All the current evolutionary tracks predict systematically larger
masses for given luminosities than our observationally derived ones,
especially at the high end. Moreover, our study confirms that the
evolutionary tracks of the low mass stars in SMC are not in agreement with
the observations as they do not extend sufficiently blueward and do
not penetrate deep enough into the instability strip, or not at all.
The inference of masses directly from the observational database
yields a novel and strong constraint on evolutionary calculations.
Key words: stars: oscillations / stars: Cepheids / stars: evolution, Magellanic Clouds, distance moduli
© ESO, 2001
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