Exoplanets 101

exoplanet Demographics: planetary diversity

What are exoplanets? Simply, they're planets beyond our solar system. We've found nearly 6,000 so far, categorized mainly as Gas Giants, Super-Earths, and Rocky Worlds. Gas Giants resemble a super-sized Jupiter and make up 30% of discoveries. Super-Earths and Mini-Neptunes, the most commonly found planets around sunlike stars, comprise 60% yet are absent in our own solar system. Rocky Worlds like Earth are rare finds but could be more common than we think; they're just harder to spot with current techniques. The hunt for these elusive rocky planets poses exciting challenges, especially as they're the most likely candidates for harboring life.

The small planet radius gap

Super-Earths and Sub-Neptunes are the most common exoplanets we currently detect, but they're separated by a curious 'Radius Gap' as shown in the plot. Do planets not form in this size range, or do they simply not last? Their sizes can actually change over time due to two main 'mass-loss' mechanisms:

  1. Photoevaporation: High-energy UV radiation from the host star can energize the planet's atmosphere enough to escape its gravity.

  2. Core Cooling: Newly-formed planets are hot and gradually cool down. This cooling can make the atmosphere 'light' enough to escape.

These mechanisms keep astronomers questioning the evolution of these intriguing worlds

My research focuses on ways to better understand these physical mass-loss mechanisms.