  It is well-established that the magnitude of the incident stellar flux is the
single most important factor in determining the day-night temperature gradients
and atmospheric chemistries of short-period gas giant planets. However it is
likely that other factors, such as planet-to-planet variations in atmospheric
metallicity, C/O ratio, and cloud properties, also contribute to the observed
diversity of infrared spectra for this population of planets. In this study we
present new 3.6 and 4.5 micron secondary eclipse measurements for five
transiting gas giant planets: HAT-P-5b, HAT-P-38b, WASP-7b, WASP-72b, and
WASP-127b. We detect eclipses in at least one bandpass for all five planets and
confirm circular orbits for all planets except for WASP-7b, which shows
evidence for a non-zero eccentricity. Building on the work of Garhart et al.
(2020), we place these new planets into a broader context by comparing them
with the sample of all planets with measured Spitzer secondary eclipses. We
find that incident flux is the single most important factor for determining the
atmospheric chemistry and circulation patterns of short-period gas giant
planets. Although we might also expect surface gravity and host star
metallicity to play a secondary role, we find no evidence for correlations with
either of these two variables.
