Encyclopedia of Astrobiology

2015 Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James (Jim) CleavesII, Daniele L. Pinti, José Cernicharo Quintanilla, Daniel Rouan, Tilman Spohn, Stéphane Tirard, Michel Viso


  • Jörg KnollenbergEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-3-662-44185-5_5212


(101955) Bennu (formerly designated as 1999 RQ36) is a carbonaceous near-Earth asteroid (NEA) with a diameter of ~500 m. The orbit of Bennu is potentially hazardous for the Earth with an estimated cumulative impact probability of 3.7 10−4 for an impact on the Earth until the end of the next century. The bulk density of the asteroid is 1,260 ± 70 kg m−3, and the disk-averaged thermal inertia is 310 ± 70 J m−2 K−1 s−1/2 which is significantly lower compared to other NEAs. These values suggest a rubble pile internal structure covered by regolith with a typical grain size of the order of a few mm to 1 cm.

(101955) Bennu is the target of the NASA space mission OSIRIS-REx which is scheduled for launch in 2016 and shall return a sample of the  asteroid to the Earth in 2023.

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Institute of Planetary ResearchGerman Aerospace CenterBerlinGermany