| Authors : | Mami Deka1, Earl P. Bellinger2,3,4, Shashi M. Kanbur5, Sukanta Deb1,6, Anupam Bhardwaj7,
Hugh Riley Randall5, Selim Kalici5, Susmita Das8 |
| Authors Affiliation: | 1 Department of Physics, Cotton University, Panbazar, Guwahati 781001, Assam, India
2 Max Planck Institute for Astrophysics, Garching, Germany
3 Department of Astronomy, Yale University, CT, USA
4 Stellar Astrophysics Centre, Aarhus, Denmark
5 Department of Physics, State University of New York Oswego, Oswego, NY 13126, USA
6 Space and Astronomy Research Center, Cotton University, Panbazar, Guwahati 781001, Assam, India
7 INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, I-801301, Napoli, Italy
8 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network (ELKH), Konkoly Thege Miklós út 15-17, H-1121, Budapest, Hungary |
| Abstract : | Classical Cepheid, one type of pulsating variable is vital for measuring cosmic distances thanks to their period-luminosity (PL) relation and contributes to the ongoing debate surrounding the "Hubble constant". The instability strip (IS) is the home to the classically pulsating stars such as Classical Cepheids, Type II Cepheids, RR-Lyraes, δ-Scuti stars. The slope and intercept of PL relation are strongly coupled with the slope and intercept of IS edges (Simon & Young, 1997). A steeper/shallower instability region implies a steeper/shallower PL relation for a certain stellar population. Analysis of IS will provide us with new insights into the properties of Cepheids and thereby contribute to improving the PL relation. However, the internal structure of the IS is still unclear. What is the exact physical condition that determines the required depth of the He II region that makes these stars variable while entering the IS through the blue/hot edge? What is the other physical mechanism that is making these stars again steady while leaving the IS through the red/cool edge? How these physical processes are influenced by metallicity, temperature, mass, etc.? I intend to present our recent findings on this topic, both from observational and theoretical perspectives.
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