Discovery of resonating integration modes in triple-mode high-amplitude $δ$ Scuti stars: A new evolutionary phase indicator

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Hauptverfasser: Niu, Jia-Shu, Xue, Hui-Fang
Format: Preprint
Veröffentlicht: 2025
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author Niu, Jia-Shu
Xue, Hui-Fang
author_facet Niu, Jia-Shu
Xue, Hui-Fang
contents High-amplitude $δ$ Scuti stars (HADS) that pulsate in their first three radial modes are rare in current samples. Here, we analyse five such triple-mode HADS observed by the Transiting Exoplanet Survey Satellite (TESS) and {report that the previously considered second overtone mode ($f_2$) is actually the non-radial component of a resonating integration mode (RI mode, resulting from resonance between a radial p-mode and a non-radial p-g mixed mode), which shows significant amplitude and frequency variations over short timescales (approximately 20 days).} This RI mode appears to be widespread among these stars. Notably, all five stars are in the post-main sequence evolutionary phase, actively crossing the Hertzsprung gap. These stars offer valuable insights into stellar evolution during the Hertzsprung gap, which is one of the most rapid evolutionary stages in a star's life.
format Preprint
id arxiv_https___arxiv_org_abs_2505_03653
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Discovery of resonating integration modes in triple-mode high-amplitude $δ$ Scuti stars: A new evolutionary phase indicator
Niu, Jia-Shu
Xue, Hui-Fang
Solar and Stellar Astrophysics
High-amplitude $δ$ Scuti stars (HADS) that pulsate in their first three radial modes are rare in current samples. Here, we analyse five such triple-mode HADS observed by the Transiting Exoplanet Survey Satellite (TESS) and {report that the previously considered second overtone mode ($f_2$) is actually the non-radial component of a resonating integration mode (RI mode, resulting from resonance between a radial p-mode and a non-radial p-g mixed mode), which shows significant amplitude and frequency variations over short timescales (approximately 20 days).} This RI mode appears to be widespread among these stars. Notably, all five stars are in the post-main sequence evolutionary phase, actively crossing the Hertzsprung gap. These stars offer valuable insights into stellar evolution during the Hertzsprung gap, which is one of the most rapid evolutionary stages in a star's life.
title Discovery of resonating integration modes in triple-mode high-amplitude $δ$ Scuti stars: A new evolutionary phase indicator
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2505.03653