A preliminary discovery is the first, original observation of new asteroid. The asteroid must be observed a second time within the next 7-10 days. If it is, then the discovery is changed to provisional status by the Minor Planet Center (MPC). Asteroid discoveries with provisional status are maintained in the MPC database for many years, until there have been a sufficient number of observations to fully determine the orbit. That process typically takes 6 years, at which point the asteroid is numbered and cataloged by the International Astronomical Union. Numbered asteroids can be named by their student discoverers.
A Provisional Discovery is the confirmed and formally recognized asteroid discovery, as endorsed by international agencies concerned, having the highest value among all the discoveries/observations credited.