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Department of Astronomy Colloquium Series Presents:

Dr. Nicolas Cowan, Professor, Department of Earth & Planetary Sciences, McGill University
Thursday, March 30, 2017
3:40-4:30 PM
411 West Hall Map
Energy Budgets of Short-Period Planets

Most planetary systems do not resemble ours. Nature likes to produce planets with sizes between those of Earth and Neptune, but located interior to Mercury's orbit. Likewise, the vast majority of temperate terrestrial planets orbit close to dim red stars and experience dramatically different stellar forcing than the Earth. Since we have no analogs to these worlds in our Solar System, and since we do not yet have robust predictive models of planetary climate, we must observe them in order to understand their atmospheric composition, cloud formation, and wind patterns. But the small star-planet separations of short-period planets precludes directly imaging them. Instead, we monitor the unresolved planet's reflectance and emission as a function of orbital phase to infer its albedo, the efficiency of its day-night heat transport, and, in the case of planets subject to seasons, its thermal inertia. Multi-wavelength measurements also constrain atmospheric composition and vertical temperature structure. Such inferences are particularly sensitive to measurement uncertainty, however, and the accuracy of these measurements has previously been over-stated. Fortunately, improved analysis techniques and next-generation instruments should allow us to resolve outstanding questions about short-period gas giants, and to extend our methods to temperate terrestrial planets orbiting nearby red dwarfs.
Building: West Hall
Event Type: Lecture / Discussion
Tags: Astronomy, Physics, Science
Source: Happening @ Michigan from Department of Astronomy, Michigan Institute for Research in Astrophysics