  Hot Jupiters on extremely short-period orbits are expected to be unstable to
tidal dissipation and spiral toward their host stars. That is because they
transfer the angular momentum of the orbital motion through tidal dissipation
into the stellar interior. Although the magnitude of this phenomenon is related
to the physical properties of a specific star-planet system, statistical
studies show that tidal dissipation might shape the architecture of hot Jupiter
systems during the stellar lifetime on the main sequence. The efficiency of
tidal dissipation remains poorly constrained in star-planet systems. Stellar
interior models show that the dissipation of dynamical tides in radiation zones
could be the dominant mechanism driving planetary orbital decay. These
theoretical predictions can be verified with the transit timing method. We
acquired new precise transit mid-times for five planets. They were previously
identified as the best candidates for which orbital decay might be detected.
Analysis of the timing data allowed us to place tighter constraints on the
orbital decay rate. No statistically significant changes in their orbital
periods were detected for all five hot Jupiters in systems HAT-P-23, KELT-1,
KELT-16, WASP-18, and WASP-103. For planets HAT-P-23 b, WASP-18 b, and WASP-103
b, observations show that the mechanism of the dynamical tides dissipation
probably does not operate in their host stars, preventing them from rapid
orbital decay. This finding aligns with the models of stellar interiors of
F-type stars, in which dynamical tides are not fully damped due to convective
cores. For KELT-16 b, the span of transit timing data was not long enough to
verify the theoretical predictions. KELT-1 b was identified as a potential
laboratory for studying the dissipative tidal interactions of inertial waves in
a convective layer.
