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Astronomy Colloquium
Explanetary Systems-What do they teach about the Solar System?
Date: Thursday, December 2nd
Time: 3:30 pm
Place: 4421 Sterling Hall
Speaker: George Rieke, University of Arizona
Abstract: When we set out seriously to search for other planetary systems nearly two decades ago, it seemed obvious that they would be analogs to the Solar System. Some could possibly be abodes for life, and therefore would illuminate our past and future. Now we know of more than 500 exoplanets, but they represent an evolutionary end point completely foreign to us and perhaps in most cases hostile to the development of sophisticated life. Is this a selection effect, resulting from the bias of our two most successful search techniques toward massive planets close to their stars? A third approach, study of planetary debris disks, brings a countervailing bias toward planetesimal systems on large orbits. It has been equally successful with more than 300 systems known. They are marked by evidence for planetesimal belts analogous to the Kuiper Belt and in some cases the asteroid belt. Their resemblance to the Solar System lets us study them to constrain our models of how our system formed and evolved; they are also signposts for the detection of massive planets on orbits far from their stars. I will describe the current knowledge of debris systems, outlining evidence for: 1.) a general decay of planet-building activity similar to that deduced for the Solar System; 2.) occasional large collisions analogous at least in destructive power to the one that led to the formation of our moon; 3.) the behavior of planetesimals near the ice line, the possible sources of volatile gases on Earth; and 4.) similarities and differences of the outer planetesimal zones in other systems to our Kuiper Belt.
Host: Astro Dept
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