  Common envelopes are thought to be the main method for producing tight
binaries in the universe as the orbital period shrinks by several orders of
magnitude during this phase. Despite their importance for various evolutionary
channels, direct detections are rare, and thus observational constraints on
common envelope physics are often inferred from post-CE populations. Population
constraints suggest that the CE phase must be highly inefficient at using
orbital energy to drive envelope ejection for low-mass systems and highly
efficient for high-mass systems. Such a dichotomy has been explained by an
interplay between convection, radiation and orbital decay. If convective
transport to the surface occurs faster than the orbit decays, the CE
self-regulates and radiatively cools. Once the orbit shrinks such that
convective transport is slow compared to orbital decay, a burst occurs as the
release of orbital energy can be far in excess of that required to unbind the
envelope. With the anticipation of first light for the Rubin Observatory, we
calculate light curve models for convective common envelopes and provide the
time evolution of apparent magnitudes for the Rubin filters. Convection imparts
a distinct signature in the light curves and lengthens the timescales during
which they are observable. Given Rubin limiting magnitudes, convective CEs
should be detectable out to distances of ~8 Mpc at a rate of ~0.3 per day and
provide an intriguing observational test of common envelope physics.
