SIMBAD references

2024ApJ...963..155C - Astrophys. J., 963, 155 (2024/March-2)

Two High-amplitude δ Scuti-γ Doradus Hybrids Constrained by the Radial Fundamental p and Equally Spaced g Modes.

CHEN X., ZHANG X., LI Y. and SU J.

Abstract (from CDS):

Based on 2 minutes cadence TESS data, we investigate pulsations of TIC 65138566 and TIC 139729335 and discover them to be two new high-amplitude δ Scuti stars with equally spaced g modes. We recognize the radial fundamental mode f1 = 18.3334 c d–1 and the first overtone f3 = 23.6429 c d–1 for TIC 65138566, and identify the highest peak f1 = 19.0955 c d–1 as the radial fundamental mode for TIC 139729335. For g modes, both stars display a regular period spacing of 2413 s. Through detailed seismological analysis, we deduce that these period-spacing patterns correspond to modes with ℓ = 1. Moreover, our analysis reveals that with increases in masses and metallicities, the star should display a higher degree of evolution to match a specific period spacing Π0. Conversely, the star should have a lower extent of evolution to match the radial fundamental mode. These two contradictory behaviors allow us to precisely obtain stellar physical parameters. TIC 65138566 and TIC 139729335 are determined to be two main-sequence stars that have almost the same range of masses and metallicities, with M = 1.36 ± 0.06 M⊙ and Z = 0.005 ± 0.002. The hydrogen abundance in the core of TIC 65138566 is estimated to be about 0.28, while TIC 139729335 has a slightly higher value of around 0.31. Finally, we suggest that the high-amplitude δ Scuti-γ Doradus star TIC 308396022 is a main-sequence star with M = 1.54 ± 0.08 M⊙, Z = 0.007 ± 0.001, and Xc = 0.18 ± 0.02.

Abstract Copyright: © 2024. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Asteroseismology - Delta Scuti variable stars - Gamma Doradus variable stars

Simbad objects: 13

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