York University-led research provides new insights on origin, evolution of asteroid Bennu

Research, published in Science Advances, led by Lassonde School of Engineering Professor Michael Daly, provides new insights into the formation of near-Earth asteroid Bennu, and how it evolved into its present shape.

Daly, the lead instrument scientist for Canada’s contribution of the OSIRIS-REx Laser Altimeter (OLA), along with a team of researchers, used data from OLA to create a 20-centimetre resolution model of Bennu’s roughly 500-metre diameter shape – the most detailed asteroid model to date. OLA and the Canadian science team are funded by the Canadian Space Agency.

OSIRIS-REx Artist's Concept OSIRIS-REx extends its sampling arm as it moves in to make contact with the asteroid Bennu.

An artist's concept drawing of OSIRIS-REx
OSIRIS-REx extends its sampling arm as it moves in to make contact with the asteroid Bennu

Bennu is a near-Earth asteroid that formed in the asteroid belt and found its way into a closer proximity to Earth due to gravitational interactions with giant planets and forces due to heating from the Sun. 

The analysis of this shape concludes that Bennu’s rounder southern hemisphere is caused by a hemispherical difference in the number of large boulders – a consequence of its formation – that are holding back finer surface material. The research also provides evidence of a past global, spin-related partial disruption that is still expressed in Bennu’s shape.

“Our research on this type of asteroid is important in understanding the evolution the solar system and of the Earth, because it was this type of asteroid that delivered water and organics to the Earth,” says Daly, director of York’s Centre for Research in Earth and Space Science (CRESS). 

OSIRIS-REx – the first-ever sampling mission by NASA to the distant asteroid Bennu – was successfully launched into space on Sept. 8, 2016 from Cape Canaveral Air Force Station in Florida. The mission aims to revolutionize our understanding of asteroids and the origins of the universe. Daly was the scientific lead for the mission.

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