An occultation is really the same thing as a total solar eclipse – just replace the moon with an asteroid and a distant star for the Sun. If you are in the right place at the right time, the asteroid will pass in front of the star for a short time, usually just for a few seconds. Knowing when the event happens and for how long the star was covered up is the key to extracting useful information from which we can learn more about the object and sometimes even something about the star.
Learn more about Lucy occultation science here.
International Occultation Timing Association (IOTA) website