Gaia and the new comets from the Oort cloud

► We analyze in detail the role of stars in injection of comets from the Oort cloud. ► We use 5 Gyr simulations and focus on comets injected during quiescent period. ► Most injected comets require the intervention of a star in all parts of the cloud. ► We judge the detectability of the culprit stars by the Hipparcos and Gaia missions. ► The chances to identify those culprits will be revolutionized by the Gaia data.