A search of reactivated comets

Abstract

Dormant or near-dormant short-period comets can unexpectedly regain ability to eject dust. In many known cases, the resurrection is short-lived and lasts less than one orbit. However, it is possible that some resurrected comets can remain active in latter perihelion passages. We search the archival images of various facilities to look for these "reactivated" comets. We identify two candidates, 297P/Beshore and 332P/Ikeya-Murakami, both of which were found to be inactive or weakly active in the previous orbit before their discovery. We derive a reactivation rate of $\sim0.007~\mathrm{comet}^{-1}~\mathrm{orbit}^{-1}$, which implies that typical short-period comets only become temporary dormant for less than a few times. Smaller comets are prone to rotational instability and may undergo temporary dormancy more frequently. Next generation high-cadence surveys may find more reactivation events of these comets.