2025ApJ...995..188Y -
Astrophys. J., 995, 188 (2025/December-3)
Pulsation Mode Identification and Classification of 46 High-amplitude δ Scuti Stars from 50 Candidates with TESS Observations.
YANG T. and ZUO Z.
Abstract (from CDS):
Asteroseismic modeling of high-amplitude δ Scuti (HADS) variables critically depends on their accurate classification, which provides robust constraints on stellar physical parameters. As a foundational step in this direction, we present a detailed analysis of the pulsational behavior of 50 HADS star candidates using high-precision photometric data from the Transiting Exoplanet Survey Satellite. We confirm 46 as genuine HADS variables, with 40 stars having their dominant frequencies identified for the first time. Among them, 7 pulsate solely in the fundamental mode, 21 exhibit the fundamental mode alongside at least one low-amplitude nonradial mode, 5 are pure double-mode pulsators (the fundamental and first-overtone modes), and 13 show double-mode pulsations accompanied by additional low-amplitude nonradial modes. The remaining four stars are classified as other types of variables: two (TIC 69546708 and TIC 110937533) are confirmed hot subdwarfs, one (TIC 8765832) is a cataclysmic variable, and one (TIC 32302937) is a likely hot subluminous star, but it requires further spectroscopic confirmation. We investigate the period-luminosity relation, also known as the Leavitt law, for these 46 confirmed HADS stars, deriving a revised relation: ${M}_{V}=(-3.31\pm 0.39)\,{\rm{log}}\,P+(-1.68\pm 0.39)$. This result is consistent with previous studies. Their distribution in the Hertzsprung-Russell diagram indicates that HADS stars are not strictly confined to be within a narrow instability strip that was previously found but can extend beyond it, with a distribution toward lower temperatures. The refined classifications presented here establish a high-quality sample for precise asteroseismic modeling and enhance the potential for future machine-learning-assisted searches and classifications of HADS stars in large-scale photometric surveys.
Abstract Copyright:
© 2025. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Delta Scuti variable stars - Stellar oscillations - Asteroseismology
Status at CDS
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Simbad objects:
54
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