PAOC Colloquium: Nicolas Cowan
|April 29th, 2019
Title: The Climate of Short-Period Planets
Abstract: Starting in the mid nineties, astronomers began discovering planets orbiting other stars. The easiest exoplanets to detect, and hence the first to be detected, were Jovian worlds in close orbits about their stars, so-called "hot Jupiters". A few decades later, we are able to not only detect such planets, but also probe their atmospheres using a variety of clever remote sensing techniques. I will first review how we detect the longwave radiation from exoplanets. Then I will provide highlights of what we have learned about hot Jupiters, including transonic winds, clouds made of rocks, molecular dissociation, and magnetic drag. Along the way, I will try to highlight the subtle ways that the atmospheres of hot Jupiters differ from the Earth's: thinking about these strange worlds does not require tossing out everything you know, merely taking a few steps back! Time permitting, I will then briefly discuss the climates of short-period planets orbiting red dwarf stars. These are by far the most abundant temperate rocky planets in the Galaxy and near-term instruments will allow us to probe their atmospheres using the same techniques currently being used on bigger and hotter planets.