Nicole Thom, Space Studies master’s student, will defend her thesis as follows. Please show your support by attending.
When: Thursday, July 12, 2012 at 2:00 pm (Central)
Where: Ryan Hall, Room 111
Title: "Atmospheric Mass Loss and Orbital Evolution of Exoplanets"
Topic: With the discovery of hundreds of exoplanet systems, our understanding of planet formation has changed entirely. In particular, the discovery of a large population of gas and ice giant planets within a few hundredths of an AU of their host stars has required substantial revisions to previous planet formation and evolution paradigms. These planets likely formed farther from their host stars and migrated in to their current orbit, but the details of their formation and migration are still unclear. The distribution of the planets' semi-major axes and masses provide clues as to how this migration may have occurred. However, once the planets near their current close-in orbits, they are subject to dramatic effects that can change their masses and orbits. For example, intense stellar ultraviolet flux can drive significant mass loss from the atmospheres of these planets. Tidal forces, meanwhile, cause close-in planets to spiral into their host stars on the timescale of a few billion years.
When the effects of tides and mass loss are coupled, they may help to explain a gap in distribution of the plot of mass versus semi-major axes for close-in planets. I am investigating how these processes together have shaped the observed masses and orbits of close-in planets. To do this, I am using the programming language IDL to model the evolution of planets both moving back in time to around 0.1 Gyr after formation and forward into the future until the destruction of the planet. Tracking the evolutionary changes for a whole population of planets will allow us to begin to constrain the initial population of planets, as well as to better understand the origin of close-in planets.
******Those unable to attend in person may view the live webcast via Connect Pro******