Atmospheric Signatures of Giant Exoplanet Formation by Pebble Accretion

Understand

Atmospheric chemical abundances of giant planets lead to important constraints on planetary formation and migration.

• Studies have shown that giant planets that migrate through the protoplanetary disk can accrete substantial amounts of oxygen-rich planetesimals, leading to super-solar metallicities in the envelope and solar or sub-solar C/O ratios.
• Pebble accretion has been demonstrated to play an important role in core accretion and to have growth rates that are consistent with planetary migration.
• The high pebble accretion rates allow planetary cores to start their growth beyond 10 AU and subsequently migrate to cold (>~ 1 AU), warm (~0.1 AU- 1AU) or hot (<~ 0.1 AU) orbits.