English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present a careful and detailed light curve analysis of RR Lyrae stars in the Small Magellanic Cloud (SMC) discovered by the Optical Gravitational Lensing Experiment (OGLE) project. Out of 536 single‐mode RR Lyrae stars selected from the data base, we have investigated the physical properties of 335 ‘normal‐looking’ RRab stars and 17 RRc stars that have good quality photometric light curves. We have also been able to estimate the distance modulus of the cloud which is in good agreement with those determined from other independent methods. The Fourier decomposition method has been used to study the basic properties of these variables. Accurate Fourier decomposition parameters of 536 RR Lyrae stars in the OGLE‐II data base are computed. Empirical relations between the Fourier parameters and some physical parameters of these variables have been used to estimate the physical parameters for the stars from the Fourier analysis. Further, the Fourier decomposition of the light curves of the SMC RR Lyrae stars yields their mean physical parameters as  and   M V  = 0.78 ± 0.02  for 335 RRab variables and  and   M V  = 0.76 ± 0.05  for 17 RRc stars. Using the absolute magnitude together with the mean magnitude, intensity‐weighted mean magnitude and the phase‐weighted mean magnitude of the RR Lyrae stars, the mean distance modulus to the SMC is estimated to be 18.86 ± 0.01, 18.83 ± 0.01 and 18.84 ± 0.01 mag, respectively, from the RRab stars. From the RRc stars, the corresponding distance modulus values are found to be  18.92 ± 0.04, 18.89 ± 0.04  and  18.89 ± 0.04  mag, respectively. Since the Fourier analysis is a very powerful tool for the study of the physical properties of the RR Lyrae stars, we emphasize the importance of exploring the reliability of the calculation of Fourier parameters together with the uncertainty estimates keeping in view the large collections of photometric light curves that will become available from variable star projects of the future.

Physical parameters of the Small Magellanic Cloud RR Lyrae stars and the distance scale