The emphasis of Part B of the Exoplanets course is on the “exterior” of planets, namely, from the upper atmosphere and beyond. Planets do not exist in empty space, but they are rather embedded in the particle, magnetic and radiation environments of their host stars. As a consequence, the interaction between planets and their host stars leads to escape of planetary atmospheres, shapes (and sometimes induces) planetary magnetospheres, and affects the space weather on a planet.
This course focuses on Space Physics, and covers the following topics:
Planetary upper atmospheres: atmospheric escape (thermal vs non-thermal); Jeans escape; hydrodynamic escape and energy-limit approximation; primary and secondary atmospheres; detection of escaping atmospheres in exoplanets
Planetary magnetospheres: magnetism in solar system planets, intrinsic magnetosphere, induced magnetosphere, magnetopause distance, ionopause, magnetic fields in exoplanets.
Solar and stellar activity: spot cycle, flares, magnetism and proxies for magnetic activity; effects of stellar activity on exoplanet detection.
The interplanetary medium — solar and stellar winds: basic concepts of fluid dynamics, overview of stellar winds over the HR diagram, forces driving a stellar wind, thermally-driven winds, winds of a magnetic rotator, Alfven surface, mass- and angular-momentum losses, evolution of stellar rotation.
Space weather: origin, impacts, events and mitigation.
Outcome:
On successful completion of this course, students should be able to:
Derive the equations responsible for the stability of planetary atmospheres and magnetospheres
Explain the key processes responsible for solar and stellar activity and their space weather effects on (exo)planets
Explain the physics of winds of planet-hosting stars; derive the basic wind equations and evaluate the wind forcing on (exo)planets
