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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

(Volume 88 - Année 2019 — Actes de colloques — 2nd Belgo-Indian Network for Astronomy & Astrophysics (BINA) workshop - October 2018 - Brussels, Belgium)
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Mots-clés : étoiles, variables, Céphéides, RR Lyrae, pulsations, galaxies, nuages magellaniques

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

To cite this 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.

About: Harinder Pal Singh

Department of Physics & Astrophysics, University of Delhi, Delhi 110007, India, hpsingh@physics.du.ac.in

About: Susmita Das

Department of Physics & Astrophysics, University of Delhi, Delhi 110007, India

About: Anupam Bhardwaj

Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China

About: Shashi Kanbur

State University of New York, Oswego, NY 13126, USA

About: Marcella Marconi

INAF-Osservatorio astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy