A possible satellite of (146) Lucina has been suggested by the observation of an occultation of a star by this asteroid. Such an observation is similar to a total solar eclipse: a small area on Earth will see the star disappering during the occultation. The size of this area is the one of the asteroid since the star is very far from us. The duration of the occultation combined with the apparent velocity of the asteroid will provide the size of the object. At the time of this observation, the theoretical prediction of the area on Earth where the total occultation will be observable was not known with a sufficient accuracy needing observers on a large zone on Earth as shown on the map below.
Thanks to a simultaneous observation from Meudon and Barcelona, the existence of a satellite near Lucina was suggested. On left, the photometric light curve of the occultation observed in Meudon since the astrometry suggested that the occultation was observable only in Spain.