  Near-infrared interferometers have recently imaged a number of rapidly
rotating A-type stars, finding levels of gravity darkening inconsistent with
theoretical expectations. Here, we present new imaging of both a cooler star
{\beta} Cas (F2IV) and a hotter one {\alpha} Leo (B7V) using the CHARA array
and the MIRC instrument at the H band. Adopting a solid-body rotation model
with a simple gravity darkening prescription, we modeled the stellar geometric
properties and surface temperature distributions, confirming both stars are
rapidly rotating and show gravity darkening anomalies. We estimate the masses
and ages of these rapid rotators on L-Rpol and HR diagrams constructed for
non-rotating stars by tracking their non-rotating equivalents. The unexpected
fast rotation of the evolved subgiant {\beta} Cas offers a unique test of the
stellar core-envelope coupling, revealing quite efficient coupling over the
past ~ 0.5 Gyr. Lastly we summarize all our interferometric determinations of
the gravity darkening coefficient for rapid rotators, finding none match the
expectations from the widely used von Zeipel gravity darkening laws. Since the
conditions of the von Zeipel law are known to be violated for rapidly rotating
stars, we recommend using the empirically-derived {\beta} = 0.19 for such stars
with radiation-dominated envelopes. Furthermore, we note that no paradigm
exists for self-consistently modeling heavily gravity-darkened stars that show
hot radiative poles with cool convective equators.

Solar and Stellar Astrophysics