AY 101 Lecture Notes - Lecture 15: Comet Nucleus, Solar Wind
Document Summary
Asteroids are discovered as faint moving objects against background stars. With the exception of ceres, all asteroids look star-like from earth: a single long exposure image shows an asteroid as a streak, multiple images show a fast-moving, bright asteroid best. Most asteroids orbit between mars and jupiter, but trojan asteroids move along jupiter"s orbit: the combined gravity of the sun and jupiter allows them to orbit. ~60 degrees ahead of or behind jupiter safely. Most asteroids in the inner solar system were swept up by the planets. Those between mars and jupiter were prevented from doing so mostly by. Jupiter"s gravity through orbital resonance: the kirkwood gaps are gaps in the distribution of orbital periods of asteroids due to different orbital resonances. Many asteroids (and comet nuclei) can be characterized as rubble piles : these are made of pieces of shattered planetesimals brought and held together loosely by gravity.
