Bridging theory and observations in stellar pulsations: The impact of convection and metallicity on the instability strips of Classical and Type-II Cepheids
arxiv(2024)
摘要
The effect of metallicity on the theoretical and empirical period-luminosity
(PL) relations of Cepheid variables is not well understood and remains a highly
debated issue. Here, we examine empirical colour-magnitude diagrams (CMDs) of
Classical and Type-II Cepheids in the Magellanic Clouds and compare those with
the theoretically predicted instability strip (IS) edges. We explore the
effects of incorporating turbulent flux, turbulent pressure, and radiative
cooling into the convection theory on the predicted IS at various metallicities
using MESA-RSP. We find that the edges become redder with the increasing
complexity of convection physics incorporated in the fiducial convection sets,
and are similarly shifted to the red with increasing metallicity. The inclusion
of turbulent flux and pressure improves the agreement of the red edge of the
IS, while their exclusion leads to better agreement with observations of the
blue edge. About 90
bluest and reddest edges across the considered variations of turbulent
convection parameters. Furthermore, we identify and discuss discrepancies
between theoretical and observed CMDs in the low effective temperature and high
luminosity regions for stars with periods greater than 20 days. These
findings highlight the potential for calibrating the turbulent convection
parameters in stellar pulsation models or the prediction of a new class of
rare, long-period, 'red Cepheids', thereby improving our understanding of
Cepheids and their role in cosmological studies.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要