Fermi Gamma-ray Space Telescope

Constraints on asteroid abundance at the one-meter scale from Fermi LAT observations

J. Vandenbroucke
S. Digel, I. Moskalenko, E. Orlando, T. Porter

Abstract:

Gamma rays of energy 0.1 to 1 GeV provide a unique probe of small solar system bodies (asteroids). The mechanism is similar to that of gamma-ray emission from the Moon, Sun, and Earth?s atmosphere: cosmic rays interact with material in the solar system bodies to produce particle showers including gamma rays. While individual objects cannot be resolved, diffuse emission is in principle detectable, particularly within the ecliptic plane. Because emission is only detectable from the limb of each body (due to absorption) and small bodies are more numerous than large bodes, the emission is dominated by objects of order one meter in diameter. Because this size scale is inaccessible by other methods, gamma rays provide a unique probe of small solar system bodies. We present results from a search for this asteroid signal in Fermi LAT data.