101955 Bennu
101955 Bennu (provisional designation 1999 RQ36) is a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999.
 Mosaic image of Bennu consisting of 12 PolyCam images collected on 2 December 2018 by OSIRIS-REx from a range of 24 km (15 mi). | |||||||||||||||||
| Discovery[1] | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Discovered by | LINEAR | ||||||||||||||||
| Discovery site | Lincoln Lab's ETS | ||||||||||||||||
| Discovery date | 11 September 1999 | ||||||||||||||||
| Designations | |||||||||||||||||
| MPC designation | (101955) Bennu | ||||||||||||||||
| Pronunciation | /bɛˈnuː/ | ||||||||||||||||
Named after | Bennu | ||||||||||||||||
| 1999 RQ36 | |||||||||||||||||
| Apollo · NEO · PHA | |||||||||||||||||
| Orbital characteristics[1] | |||||||||||||||||
| Epoch 31 July 2016 (JD 2457600.5) | |||||||||||||||||
| Uncertainty parameter 0 | |||||||||||||||||
| Observation arc | 13.36 yr (4880 days) | ||||||||||||||||
| Aphelion | 1.3559 au (202.84 Gm) | ||||||||||||||||
| Perihelion | 0.89689 au (134.173 Gm) | ||||||||||||||||
| 1.1264 au (168.51 Gm) | |||||||||||||||||
| Eccentricity | 0.20375 | ||||||||||||||||
| 1.20 yr (436.65 d) | |||||||||||||||||
Average orbital speed | 28.0 km/s (63,000 mph) | ||||||||||||||||
| 101.7039° | |||||||||||||||||
Mean motion | 0° 49m 28.056s / day | ||||||||||||||||
| Inclination | 6.0349° | ||||||||||||||||
| 2.0609° | |||||||||||||||||
| 66.2231° | |||||||||||||||||
| Earth MOID | 0.0032228 au (482,120 km) | ||||||||||||||||
| Venus MOID | 0.194 au (29,000,000 km)[2] | ||||||||||||||||
| Mars MOID | 0.168 au (25,100,000 km)[2] | ||||||||||||||||
| Jupiter MOID | 3.877 au (580.0 Gm) | ||||||||||||||||
| TJupiter | 5.525 | ||||||||||||||||
| Proper orbital elements[3] | |||||||||||||||||
Proper eccentricity | 0.21145 | ||||||||||||||||
Proper inclination | 5.0415° | ||||||||||||||||
Proper mean motion | 301.1345 deg / yr | ||||||||||||||||
Proper orbital period | 1.19548 yr (436.649 d) | ||||||||||||||||
| Physical characteristics[6] | |||||||||||||||||
| Dimensions | 282.37 × 268.05 × 249.25 ± 0.06 m | ||||||||||||||||
Mean radius | 245.03±0.08 m | ||||||||||||||||
Equatorial radius | 282.37±0.06 m | ||||||||||||||||
Polar radius | 249.25±0.06 m | ||||||||||||||||
| 0.782±0.004 km2 | |||||||||||||||||
| Volume | 0.0615±0.0001 km3 | ||||||||||||||||
| Mass | (7.329±0.009)×1010 kg | ||||||||||||||||
Mean density | 1.190±0.013 g/cm3 | ||||||||||||||||
Equatorial surface gravity | 6 micro-g[4] | ||||||||||||||||
| 4.296057±0.000002 h | |||||||||||||||||
| 177.6±0.11° | |||||||||||||||||
North pole right ascension | +85.65±0.12° | ||||||||||||||||
North pole declination | −60.17±0.09° | ||||||||||||||||
| 0.044±0.002 | |||||||||||||||||
| |||||||||||||||||
| B[1][6] F[7] | |||||||||||||||||
| 20.9 | |||||||||||||||||
Bennu has a 1 in 2,700 chance of hitting Earth between the year 2175 and 2199.
It is named after the Bennu, the ancient Egyptian mythological bird associated with the Sun, creation, and rebirth.
Bennu has an average diameter of 492 metres (1,614 feet).
Bennu was the target of the OSIRIS-REx mission which returned samples to Earth in 2023 for further study.
Bennu is the second-highest on the cumulative rating on the Palermo technical impact hazard scale.
It is believed that Bennu broke off from another asteroid in the asteroid belt, but the gravitational pull of Saturn dislodged it into the range of Earth.
Bennu orbits the Sun every 1.2 years. It comes within 0.002 astronomical units of the earth every 6 years.
Some believe that if Bennu enters a specific hole between the earth and the moon its orbit could change in a way that would make it likely to hit Earth.
