RR Lyrae variables in Messier 53: Near-infrared Period--Luminosity relations and the calibration using Gaia Early Data Release 3

no code implementations • 25 Dec 2020 • Anupam Bhardwaj, Marina Rejkuba, Richard de Grijs, Soung-Chul Yang, Gregory J. Herczeg, Marcella Marconi, Harinder P. Singh, Shashi Kanbur, Chow-Choong Ngeow

Multi-epoch $JHK_s$ observations, obtained with the WIRCam instrument on the 3. 6-m Canada France Hawaii Telescope, are used for the first time to estimate precise mean-magnitudes for 63 RR Lyrae stars in M53 including 29 fundamental-mode (RRab) and 34 first-overtone modes (RRc) variables.

Solar and Stellar Astrophysics Astrophysics of Galaxies

Possible evidence of hydrogen emission in the first-overtone and multi-mode RR Lyrae variables

no code implementations • 24 Dec 2020 • Xiao-Wei Duan, Xiao-Dian Chen, Li-Cai Deng, Fan Yang, Chao Liu, Anupam Bhardwaj, Hua-Wei Zhang

The nature of shock waves in non-fundamental mode RR Lyrae stars remains a mystery because of limited spectroscopic observations.

Solar and Stellar Astrophysics

When a Period Is Not a Full Stop: Light Curve Structure Reveals Fundamental Parameters of Cepheid and RR Lyrae Stars

no code implementations • 25 Nov 2019 • Earl P. Bellinger, Shashi M. Kanbur, Anupam Bhardwaj, Marcella Marconi

We quantify which aspects of light curve structure are most important in determining fundamental parameters, and find for example that the second Fourier amplitude component of RR Lyrae light curves is even more important than period in determining the effective temperature of the star.