Pulsation Models for Ultra-Low (Z=0.0004) Metallicity Classical Cepheids

Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

accepted for publication on ApJ. Table3 is in a separate file because it will appear only in electronic form. Figures 11 and 1

Scientific paper

Classical Cepheids are primary distance indicators playing a fundamental role in the calibration of the extragalactic distance scale. The possible dependence of their characteristic Period-Luminosity (PL) relation on chemical composition is still debated in the literature, and the behaviour of these pulsators at very low metallicity regimes is almost unexplored. In order to derive constraints on the application of the Period-Luminosity relation at low metal abundances, we investigate the properties of the few ultra-low metallicity (Z ~ 0.0004) Cepheids recently discovered in the Blue Compact Dwarf galaxy IZw18. To this purpose we have computed an updated and extended set of nonlinear convective models for Z=0.0004 and Y=0.24, spanning a wide range of stellar masses, and taking into account the evolutionary constraints for selected luminosity levels. As a result we are able to predict the topology of the instability strip, the variations of all the relevant quantities along the pulsation cycle, including the morphology of the light curves, the theoretical Period-Luminosity-Color, Period-Wesenheit and Period-Luminosity relations at such a low metallicity. For each of these relations we provide the appropriate coefficients for fundamental mode pulsators with Z=0.0004. By comparing these results with the properties of more metal rich Cepheids we find that the synthetic PL relations for Z=0.0004 are steeper than at higher Z, but similar to the Z=0.004 ones, thus suggesting a leveling off of the metallicity effect towards the lowest Zs.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Pulsation Models for Ultra-Low (Z=0.0004) Metallicity Classical Cepheids does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Pulsation Models for Ultra-Low (Z=0.0004) Metallicity Classical Cepheids, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pulsation Models for Ultra-Low (Z=0.0004) Metallicity Classical Cepheids will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-379858

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.