Madelyn Broome

UC Santa Cruz

“Modeling the Supersonic Winds Escaping from Exoplanets Close to Their Host Stars”

Of the nearly 5000 exoplanets that have been discovered orbiting around other stars in our galaxy, several hundred are so close to their host stars that they take anywhere from 100 days (the period of Mercury) to just 1 day to orbit around their stars. These planets are bombarded with high energy X-ray and UV radiation that heats the planets to up to 10,000 K (17,500 F), which causes their upper atmospheres to expand outwards, until the gas is moving fast enough to escape the gravitational pull of the planet. Understanding this process of mass loss due to atmospheric escape is essential to understanding the evolution of these planets throughout their lifetimes, but telescope observations alone are not able to constrain the mass loss rates – we need computational models. Therefore, we have developed an ultra-fast publicly-available model that includes important X-ray and atomic element physics not present in other such models. The speed and reliability of this code will allow it to be used to advance a number of unanswered questions in the field.


Developing an in-demand model for the escape of atmospheres from exoplanets that are close to their host stars. These planets are highly irradiated by X-rays and UV rays which heat a planet’s upper atmospheres and cause the gas to expand and flow away from the planet at supersonic speeds.

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