Bulletin de la Société Royale des Sciences de Liège Bulletin de la Société Royale des Sciences de Liège -  Volume 88 - Année 2019  Actes de colloques  2nd Belgo-Indian Network for Astronomy & Astrophysics (BINA) workshop - October 2018 - Brussels, Belgium 

Light Curve Parameters of Cepheid and RR Lyrae Variables at Multiple Wavelengths Models vs. Observations

Harinder Pal Singh
Department of Physics & Astrophysics, University of Delhi, Delhi 110007, India, hpsingh@physics.du.ac.in
Susmita Das
Department of Physics & Astrophysics, University of Delhi, Delhi 110007, India
Anupam Bhardwaj
Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China
Shashi Kanbur
State University of New York, Oswego, NY 13126, USA
Marcella Marconi
INAF-Osservatorio astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy

Abstract

We present results from a comparative study of light curves of Cepheid and RR Lyrae stars in the Galaxy and the Magellanic Clouds with their theoretical models generated from the stellar pulsation codes. Fourier decomposition method is used to analyse the theoretical and the observed light curves at multiple wavelengths. In case of RR Lyrae stars, the amplitude and Fourier parameters from the models are consistent with observations in most period bins except for low metal-abundances (Z < 0.004). In case of Cepheid variables, we observe a greater offset between models and observations for both the amplitude and Fourier parameters. The theoretical amplitude parameters are typically larger than those from observations, except close to the period of 10 days. We find that these discrepancies between models and observations can be reduced if a higher convective efficiency is adopted in the pulsation codes. Our results suggest that a quantitative comparison of light curve structure is very useful to provide constraints for the input physics to the stellar pulsation models.

Keywords : stars, variables, Cepheids, RR Lyrae, pulsations, bulge – galaxies, Magellanic Clouds

Pour citer cet article

Harinder Pal Singh, Susmita Das, Anupam Bhardwaj, Shashi Kanbur & Marcella Marconi, «Light Curve Parameters of Cepheid and RR Lyrae Variables at Multiple Wavelengths Models vs. Observations», Bulletin de la Société Royale des Sciences de Liège [En ligne], Volume 88 - Année 2019, Actes de colloques, 2nd Belgo-Indian Network for Astronomy & Astrophysics (BINA) workshop - October 2018 - Brussels, Belgium, 95-102 URL : https://popups.uliege.be/0037-9565/index.php?id=8706.