Joseph Masiero

An artist's depiction of two near-Earth asteroids passing by the Earth at a safe distance. The 18-inch Schmidt telescope now on display in the Observatory's Museum was used in the 1970s by Eleanor Helin to conduct systematic searches for asteroids whose orbits might cross that of the Earth. (ESA)

Polarimetric observations of asteroids is now a common remote sensing technique. When observed a varying phase angles, polarized light scattered from an asteroid's surface contains information about the physical properties of its topmost layer such as particle size, porosity, heterogeneity, and surface roughtness.

Most studies, however, have been done in visible light and Masiero believes that the near infrared spectrum has strong diagnostic features that have not yet been utilized. Tonight he will use the Wide-Field Infrared camera to develop polarization-phase curves of several nearby asteroids.