Connecting Planetary Composition With Formation: A New Paradigm Emerges
Extensive ground and space based surveys have now characterized the properties of thousands of exoplanets; their radii, masses, orbits around their host stars, and the beginnings of accurate measurements of the chemical compositions of their atmospheres and cores.
How are these properties linked to their formation in physically and chemically evolving protoplanetary disks wherein they accrete pebbles, planetesimals, and gas as they undergo migration?
To address this challenge, our review assembles a large and varied body of exoplanet observations as well as recent Atacama Large Millimeter Array (ALMA) and James Webb Space Telescope (JWST) observations of disk structure, chemistry, kinematics, and winds. The latest advances in theory and MHD simulations that bear on these issues are also reviewed and compared with the observations.
Taken together, this review argues that a new dynamic paradigm for planet formation is emerging wherein MHD disk winds and not disk turbulence play a central role in disk evolution and planet formation including: angular momentum transport, gap and ring formation. disk astrochemistry, and planet formation and migration.
These processes leave their mark on the resulting atmospheric composition, radii, and orbital characteristics of exoplanet populations, offering the possibility of future observational tests.
An example of the variety of known molecules and their structures in protoplanetary disks. This particular example is from the MAPS large ALMA program (Öberg et al. 2021) and represents the continuum emission (i.e. dust, in orange, bottom right panel) as well as line emission from a various molecular tracers (blue) for HD 163296. The top left panel shows a size comparison between the dust emission and the emission from the brightest CO line. The dust is much more compact than the gas suggesting that radial drift has played an important role overall. Some gas tracers trace the gas distribution more closely (13CO, H2CO, CN) while others more closely tracer the dust distribution (C2H, HC3N). Figure adapted from (Öberg et al. 2021), reproduced with permission, ©AAS — astro-ph.EP
Ralph E. Pudritz, Alex J. Cridland, Julie Inglis, Mathew Alessi
Comments: 65 pages of text, 14 pages of references, 26 figures; Review to be published as a Chapter in Handbook of Exoplanets, 2nd Edition, eds. Hans J. Deeg and Juan Antonio Belmonte (Springer). arXiv admin note: substantial text overlap with arXiv:1804.04070
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2505.22724 [astro-ph.EP] (or arXiv:2505.22724v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2505.22724
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Submission history
From: Ralph Pudritz
[v1] Wed, 28 May 2025 18:00:01 UTC (20,877 KB)
https://arxiv.org/abs/2505.22724
Astrobiology
