16 October 2014
16 October 2014
Speaker: Amy Mainzer (NASA/JPL)
Small Bodies in Our Solar System: Opportunity and Risk
The minor planets in our solar system record its tumultuous history. By studying small body physical and dynamical properties, we can gain insights into the mechanisms that formed them, set constraints on the formation of the early solar system, and quantify the frequency with which they interact with Earth. Large-area thermal infrared surveys offer the opportunity to discover large numbers of asteroids and comets, and to derive physical properties such as sizes and albedos for them. These radiometrically-derived quantities allow for improved estimates of the ages of asteroid collisional families, the thermal inertias of asteroid regoliths, and the numbers, orbital element distributions, and size frequency distributions of various subpopulations (including near-Earth asteroids). Multi-wavelength infrared observations can also be used to set constraints on the quantity of dust and volatiles emitted by comets. NASA's Wide-field Infrared Survey Explorer mission observed more than 158,000 minor planets at wavelengths ranging from 3.4 to 22 microns during its year-long prime mission in 2010 and early 2011, including ~34,000 new discoveries, significantly increasing the number of objects with well-determined diameters and albedos. The spacecraft has recently been reactivated following a 32-month hibernation period and renamed NEOWISE; it is now dedicated to surveying for near-Earth objects using its remaining 3.4 and 4.6 micron channels. Future possibilities include a more comprehensive survey for near-Earth objects based on the groundwork laid by WISE/NEOWISE.