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Discovery Circumstances

Discovery circumstances are available for selected comets and numbered asteroids, most planetary satellites, and recently discovered planets.

Small Bodies

Comet and asteroid discovery circumstances are available via the Small-Body Database Lookup tool where you can specify the object of interest and then scroll down to the “Discovery Circumstances” section and click on “show”. Here’s an example for asteroid 101955 Bennu.

Please note that discovery data are available only for numbered asteroids and selected comets. These data include the date of discovery, who discovered the object, and where it was discovered. In addition, for recently named asteroids, the citation issued for their IAU name is available.

Planetary Satellites

Planetary satellite discovery circumstances are available in a separate table which includes the satellite provisional designation, IAU number (if assigned), IAU name (if assigned), year of discovery, a list of discoverers, and references (where known).


Most of the planets (including the Earth’s moon) have been known to mankind since ancient times. The planets beyond Saturn were discovered in more recent times. These planetary discovery circumstance are avilable on a separate page.