101955 Bennu (provisional designation 1999 RQ36) is a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999. It is a potentially hazardous object that is listed on the Sentry Risk Table and has the highest cumulative rating on the Palermo Technical Impact Hazard Scale. It has a cumulative 1-in-1,750 chance of impacting Earth between 2178 and 2290 with the greatest risk being on 24 September 2182. It is named after Bennu, the ancient Egyptian mythological bird associated with the Sun, creation, and rebirth.
101955 Bennu has a mean diameter of 490 m (1,610 ft; 0.30 mi) and has been observed extensively by the Arecibo Observatory planetary radar and the Goldstone Deep Space Network.
Bennu was the target of the OSIRIS-REx mission that returned samples of the asteroid to Earth. The spacecraft, launched in September 2016, arrived at the asteroid two years later and mapped its surface in detail, seeking potential sample collection sites. Analysis of the orbits allowed calculation of Bennu's mass and its distribution. In October 2020, OSIRIS-REx briefly touched down and collected a sample of the asteroid's surface. A capsule containing the sample was returned and landed on Earth in September 2023, with distribution and analysis of the sample ongoing.
* = Have been modified recently
