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A Comparative Study of Bennu, B-Type Asteroids, and Itokawa with Implications for the OSIRIS-REx Mission

Shailyn Altepeter
Asteroid Population Characterization
Delivered As: 
Abstract Text: 

The success of the OSIRIS-REx mission depends on understanding the surface properties and mechanics of Bennu. Bennu (asteroid 101955) is a carbon-rich B-type asteroid that contains amino acids and organic molecules which might have been precursors to life. Studying Bennu is imperative because it is a Near-Earth-Asteroid (NEA) and considered potentially hazardous since it could strike Earth. Most studies have used radio and visible telescopic data to gather information about Bennu, particularly during its closest approaches in 1999, 2005, and 2012. However, Bennu is a very small asteroid (mean diameter of 492+/- 20m) and has proved challenging to study from the ground. The OSIRIS-REx mission will launch in September of 2016 and one of its mission goals is to obtain samples from Bennu’s surface for future analysis. Information from these samples is essential for enabling scientists to develop impact mitigation strategies and for understanding possible origins of life. Our objective is to compare Bennu to other well-known asteroids. We chose three main-belt B-type asteroids (e.g., 59 Elpis, 2 Pallas, and 24 Themis) and another NEA, small-sized asteroid, 25143 Itokawa. We report on properties such as albedo, orbit, density, and rotation rate of the four asteroids and compare these properties with data previously gathered for Bennu. We conclude that 59 Elpis is the most similar to Bennu, due to its comparable albedo and density. We suggest mission scientists look into these similarities to further improve their understanding of Bennu, as it will likely have many analogous physical properties as those seen on Elpis. We also suggest mission scientists extract valuable information on similarities and differences from all four asteroids studied here, especially to evaluate composition and geographic features on Bennu that are indistinguishable from telescopes on Earth.

D. De Rosa
SSERVI Identifier: 

Recognizing that science and human exploration are mutually enabling, NASA created the Solar System Exploration Research Virtual Institute (SSERVI) to address basic and applied scientific questions fundamental to understanding the Moon, Near Earth Asteroids, the Martian moons Phobos and Deimos, and the near space environments of these target bodies. As a virtual institute, SSERVI funds investigators at a broad range of domestic institutions, bringing them together along with international partners via virtual technology to enable new scientific efforts."