Asteroids

Radar observations are one of the only groundbased techniques to spatially resolve near-Earth asteroids. Images with up to 7.5-m resolution reveal a wide variety of shapes, surface features and helped to discover many binary objects. Our understanding of the nature and evolution of NEAs has changed radically in recent years, in a large part due to the information from radar images, and shape models derived from them. I will discuss current results and upcoming improved capabilities of the Arecibo planetary radar system.

 Lunar evidence of Late Heavy Bombardment has been interpreted to suggest that large-body impacting declined rapidly after about 3.8 Ga and that by 3.5 Ga the terrestrial bombardment rate was not much greater than the impact rates of today. In 1986 and 1989 Dr. Lowe and colleagues described four major layers of spherical particles in the 3.22-3.55 Ga Barberton greenstone belt (BGB), South Africa, ranging from 3,472 to 3,243 Ma, and interpreted them to represent the products of large terrestrial impacts of bolides 20-50 km in diameter.

We now know that ice in the solar system resides in at least three distinct reservoirs, known as the Oort cloud, the Kuiper belt and the main-belt comets. Dr. Jewitt will discuss the nature, distribution and significance of the ice, highlighting its connection to the formation epoch, in a style intended to be sweeping and broadly accessible.

For the first time, astronomers tracked an asteroid in space, observed its size, reflection properties and how it tumbled, then saw it crash in Earth's atmosphere over Sudan on October 7, 2008. At first, no pieces were expected to survive because the entry resulted in a massive explosion at 37 km altitude that left most of the asteroid in dust.

In late 2006, NASA's Constellation Program (CxP) sponsored a study to examine the feasibility of sending a piloted Orion spacecraft to a near-Earth Object (NEO).

Since the discovery of Ida’s companion Dactyl in 1993, the number of known multiple asteroids has been continuously increasing and ~165 of them are now known. Since 2003, Dr. Marchis and his colleagues have been conducting a large survey of these interesting and diverse populations using various ground-based telescopes and techniques, such as high angular resolution imaging, lightcurve photometry, and VIS/NIR spectroscopy, and also the Spitzer and Hubble space telescopes. Dr.

The Infrared Spectrograph (IRS) on Spitzer has observed more than 120 asteroids, several Centaurs and Kuiper Belt objects (KBOs), and satellites of the giant planets. As capabilities continue to improve, direct observations of small body populations in other systems and inter-comparisons between systems will foster significant insights into the formation and evolution of planetary systems. In this talk, Josh will present an overview of the IRS observations of small Solar System bodies, with a few representative objects highlighted for detailed discussion. 

Near Earth Asteroids (NEAs) are interesting to both planetary scientists and those who are concerned about protecting against their impacts. The first step, now well underway, is to find them (with the Spacegaurd Survey). Next we need to characterize NEAs using small spacecraft missions. We are especially interested in the sub-km NEAs, since they are the most likely to hit the Earth and also the most accessible targets for human flights beyond the Moon. This talk focuses on a low-cost rendezvous mission to NEA Apophis, with the goal of characterizing both the asteroid and its orbit.