On the incidence rate of RR Lyrae stars with non-radial modes
arXiv:2404.14373 · doi:10.1051/0004-6361/202348964
Abstract
Over the recent years, additional low-amplitude non-radial modes were detected in many of the first-overtone RR Lyrae stars. These non-radial modes form a characteristic period ratio with the dominant first-overtone mode of around 0.61. The incidence rate of this phenomenon changes from population to population. It is also strongly dependent on the quality of the analyzed data. Current models explaining these additional signals involve non-radial modes of degrees 8 and 9. Using synthetic horizontal branch populations, we investigate the incidence rate of first-overtone RR Lyrae stars with non-radial modes depending on the population properties, i.e., ages and metallicities. We compare our results with the observed results for globular clusters and the numerous collection of field first-overtone RR Lyrae stars to test the predictions of the models. We used synthetic horizontal branches combined with pulsation models to predict how the incidence rate would depend on the age and metallicity of the population. To test whether the results based on synthetic horizontal branches are realistic, we compared them to incidence rates observed by TESS in first-overtone field RR Lyrae stars, using photometric metallicity values from a newly established calibration for TESS. The analysis of synthetic horizontal branches showed that the incidence rate decreases with decreasing metallicity. We inferred photometric metallicity for RR Lyrae stars observed by TESS and showed that the theoretical predictions are in agreement with the observations. Using the same method, we also conclude that the metallicity distribution of RR Lyrae stars showing an additional mode with a period-ratio around appears to be different from that of both all first-overtone stars and those showing additional non-radial modes.
arXiv comment9 pages, 7 figures, 2 tables, accepted for publication in A&A
References in corpus (35)
- The chemical composition of the Sun
- Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
- A large stellar evolution database for population synthesis studies. I. Scaled solar models and isochrones
- Intrinsic iron spread and a new metallicity scale for Globular Clusters
- On a new theoretical framework for RR Lyrae stars I: the metallicity dependence
- RR-Lyrae-type pulsations from a 0.26-solar-mass star in a binary system
- Chemo-kinematics of the RR Lyrae: the halo and the disc
- Flavours of variability: 29 RR Lyrae stars observed with Kepler
- Kepler photometry of RRc stars: peculiar double-mode pulsations and period doubling
- [Fe/H] relations for c-type RR Lyrae Variables based upon Fourier Coefficients
- Family ties: abundances in Terzan 7, a Sgr dSph globular cluster
- Automated Nonlinear Stellar Pulsation Calculations: Applications to RR Lyrae stars. The Slope of the Fundamental Blue Edge and the First RRd Model Survey
- Overtone and multi-mode RR Lyrae stars in the globular cluster M3
- TESS observations of Cepheid stars: first light results
- First results on RR Lyrae stars with the TESS space telescope: untangling the connections between mode content, colors and distances
- An RR Lyrae family portrait: 33 stars observed in Pisces with K2-E2
- RR Lyrae From Binary Evolution: Abundant, Young and Metal-Rich
- Double-mode radial-non-radial RR Lyrae stars in the OGLE photometry of the Galactic bulge
- Discovery of a new group of double-periodic RR Lyrae stars in the OGLE-IV photometry
- On the modulation of RR Lyrae stars in the globular cluster M3
- The census of non-radial pulsation in first-overtone RR Lyrae stars of the OGLE Galactic bulge collection
- Double-mode radial-non-radial RR Lyrae stars. OGLE-IV photometry of two high cadence fields in the Galactic bulge
- Non-radial pulsation in first overtone Cepheids of the Small Magellanic Cloud
- The Absolute Magnitude of RRc Variables From Statistical Parallax
- Asteroseismology of RR Lyrae stars with non-radial modes
- Investigating light curve modulation via kernel smoothing. II. New additional modes in single-mode OGLE classical Cepheids
- Metal-Rich RRc stars in the Carnegie RR Lyrae Survey
- On the Use of Field RR Lyrae as Galactic Probes. VI. Mixed mode RR Lyrae variables in Fornax and in nearby dwarf galaxies
- Frequency analysis of OGLE-IV photometry for classical Cepheids in Galactic fields: non-radial modes and modulations
- Frequency analysis of the first-overtone RR Lyrae stars based on the Extended Aperture Photometry from the K2 data
- Time series analysis of bright TESS RRc stars: Additional modes, phase variations and more
- First Overtone Cepheids of the OGLE Magellanic Cloud Collection -- beyond radial modes
- Petersen Diagram Revolution
- To Grow Old and Peculiar: A Survey of Anomalous Variable Stars in M80 and Age Determination using K2 and Gaia
- Dependence of pulsation mode of Cepheids on metallicity