  Simultaneous core partitions are important objects in algebraic
combinatorics. Recently there has been interest in studying the distribution of
sizes among all $(s,t)$-cores for coprime $s$ and $t$. Zaleski (2017) gave
strong evidence that when we restrict our attention to $(s,s+1)$-cores with
distinct parts, the resulting distribution is approximately normal. We prove
his conjecture by applying the Combinatorial Central Limit Theorem and mixing
the resulting normal distributions.
