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  • Exploring Helium Abundance Effects on First-Overtone RR Lyrae Pulsations: Insights from Hydrodynamic Modeling and Light Curve Analysis

This content will become publicly available on January 3, 2026

Title: Exploring Helium Abundance Effects on First-Overtone RR Lyrae Pulsations: Insights from Hydrodynamic Modeling and Light Curve Analysis
Stellar pulsation features provide valuable insights into the internal structure and evolutionary states of stars. In this study, we model stellar pulsations for first-overtone RR Lyrae variables, to constrain the effects that helium abundance variations have on the emitted light curves and the radial velocity curves. We model our variables using the hydrodynamic code, Radial Stellar Pulsations (RSP) from the Modules for Experiments in Stellar Astrophysics (MESA). Our results will compare light curves taken in the V-band and from TESS data to determine if the variations in light curve shapes can be accounted for by variations in the helium abundance. In particular, we will look at the brightness and pulsation phase for the compression humps observed during pulsation cycles. The compression hump is a bump in luminosity seen in some RR Lyrae variable stars, which is caused by interactions between moving stellar layers. It may be sensitive to changes in stellar composition, including the helium abundance, because the overall amount of material in the layers of a star may influence the timing and extent of interactions. By systematically adjusting the helium abundance in the models and comparing the results to real stellar luminosity data, we aim to explore how these variations influence the magnitude and timing of the compression humps. Understanding these underlying pulsation mechanisms is crucial for improving the use of pulsating stars as standard candles in cosmological measurements.  more » « less
Award ID(s):
2319428
PAR ID:
10645135
Author(s) / Creator(s):
; ;
Publisher / Repository:
volume 245 of American Astronomical Society Meeting Abstracts, 309.04, January 2025
Date Published:
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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