Rotation-based census of blue lurkers

Blue lurkers are rejuvenated main-sequence stars hidden among normal main-sequence stars on color-magnitude diagrams of star clusters. In comparison to BLs, blue straggler stars, which formed via similar mass transfers or mergers, occupy a distinct space in color-magnitude diagrams.

Blue lurkers can be identified by their unusually faster rotation compared to similar mass stars, which is a signature of recent accretion, or by the presence of a companion (e.g., an extremely low mass white dwarf), which can only be formed by mass donation. We searched for fast-rotating stars on the main sequence of open clusters using Kepler, TESS, and spectroscopic rotation indicators, such as rotation periods and vsini measurements.