  The radius valley carries implications for how the atmospheres of small
planets form and evolve, but this feature is visible only with highly precise
characterizations of many small planets. We present the characterization of
nine planets and one planet candidate with both NASA TESS and ESA CHEOPS
observations, which adds to the overall population of planets bordering the
radius valley. While four of our planets - TOI 118 b, TOI 455 b, TOI 560 b, and
TOI 562 b - have already been published, we vet and validate transit signals as
planetary using follow-up observations for five new TESS planets, including TOI
198 b, TOI 244 b, TOI 262 b, TOI 444 b, and TOI 470 b. While a three times
increase in primary mirror size should mean that one CHEOPS transit yields an
equivalent model uncertainty in transit depth as about nine TESS transits in
the case that the star is equally as bright in both bands, we find that our
CHEOPS transits typically yield uncertainties equivalent to between two and 12
TESS transits, averaging 5.9 equivalent transits. Therefore, we find that while
our fits to CHEOPS transits provide overall lower uncertainties on transit
depth and better precision relative to fits to TESS transits, our uncertainties
for these fits do not always match expected predictions given photon-limited
noise. We find no correlations between number of equivalent transits and any
physical parameters, indicating that this behavior is not strictly systematic,
but rather might be due to other factors such as in-transit gaps during CHEOPS
visits or nonhomogeneous detrending of CHEOPS light curves.
