Strong interactions between g- and p-modes in the hybrid gamma Doradus-delta Scuti CoRoT star ID105733033

• Main Authors: Chapellier, E, Mathias, P, Weiss, W. W, Contel, D. Le, Debosscher, J
• Format: Journal Article
• Language: English
• Published: 05-03-2012
• Subjects: Physics - Solar and Stellar Astrophysics
• DOI: 10.48550/arxiv.1203.1514

CoRoT ID 105733033 is an excellent example of hybrid pulsators as it shows g-
and p-modes with almost similar amplitudes in two clearly distinct frequency
domains.
Classical Fourier analysis allows the dectection of frequencies with an
amplitude as small as 0.1 mmag up to 50c/d. The frequency spectrum of CoRoT ID
105733033 clearly consists of two distinct ranges, which are typical of gamma
Doradus and delta Scuti pulsation. Focus was placed on the identification of
linear combinations and frequencies due to the coupling between gamma Doradus
and delta Scuti modes.
We detect 198 gamma Doradus type frequencies in the range [0.25;4]c/d, of
which 180 are not combination frequencies, and 24 of them are separated by a
constant period-interval Delta P=0.03074d. According to the asymptotic theory,
these 24 frequencies correspond to a series of g-modes of the same ell-degree
and different radial orders n. We also detect 246 delta Scuti type frequencies
in the range [10.1;63.4]c/d. The dominant frequency F=12.6759c/d was identified
as the fundamental radial mode. Our most noteworthy result is that all the main
gamma Doradus frequencies f_i are also detected in the delta Scuti domain as F
+- f_i with four times smaller amplitudes. Once these frequencies were removed,
only 59 can be considered as individual delta Scuti frequencies.
A coupling between g- and p-modes is proposed to be a tool for detecting
g-modes in the Sun, but this coupling has never yet been observed. Our present
study may be valuable input to theoretical studies, addressing the mutual
influence of g- and p-mode cavities and the deviation from classical theory.
Furthermore, we identify a sequence of g-modes belonging to the same ell but
with consecutive orders n.