Where should we impact an asteroid to effectively deflect its orbit?

Recently, NASA’s Double Asteroid Redirection Test (DART) spacecraft crashed into a 170 m asteroid Dimorphos at 6.6 km/s, as the first on-orbit demonstration of deflecting an asteroid by kinetic impact. The DART spacecraft was set to impact the center of Dimorphos nearly head-on. Earth-based telescopes have now confirmed that impact successfully changed Dimorphos’ orbit period by 32 minutes, much more than expected.