  We analyze light curves of 284,834 unique K2 targets using a Gaussian process
model with a quasi-periodic kernel function. By crossmatching K2 stars to
observations from Gaia Data Release 2, we have identified 69,627 likely
main-sequence stars. From these we select a subsample of 8,977 stars on the
main-sequence with highly precise rotation period measurements. With this
sample we recover the gap in the rotation period-color diagram first reported
by \cite{McQuillan2013}. While the gap was tentatively detected in
\cite{Reinhold2020}, this work represents the first robust detection of the gap
in K2 data for field stars. This is significant because K2 observed along many
lines of sight at wide angular separation, in contrast to Kepler's single line
of sight. Together with recent results for rotation in open clusters, we
interpret this gap as evidence for a departure from the $t^{-1/2}$ Skumanich
spin down law, rather than an indication of a bimodal star formation history.
We provide maximum likelihood estimates and uncertainties for all parameters of
the quasi-periodic light curve model for each of the 284,834 stars in our
sample.
