Wasserburg Lecture: Anders Johansen, University of Copenhagen
2:00–3:00 pm Henry Hinds Laboratory, Room 101
Title: Formation Of Earth By Pebble Accretion And Impacts
Abstract: Understanding how our planet formed is a central question at the intersection of astrophysics, planetary science, cosmochemistry, and geochemistry. Observations of protoplanetary disks around young stars over the past two decades have revealed that these planet-forming disks contain large populations of millimeter- to centimeter-sized pebbles. This discovery led to the development of the pebble accretion theory, which suggests that planets primarily grow by accreting small pebbles, in contrast to the classical view that planets grow through collisions with asteroid-sized planetesimals. While pebble accretion appears essential for explaining the formation of gas giant planets far from their host stars, its role in the formation of terrestrial planets remains a subject of intense debate. I will present evidence from the isotopic and elemental composition of Earth indicating that pebble accretion played a significant role in Earth’s formation. However, the same data reveal that planetesimal accretion and the giant moon-forming impact also made substantial contributions. Therefore, I propose a hybrid accretion model for terrestrial planets and discuss its implications for volatile delivery and for the composition of primordial planet atmospheres.
Host: Fred Ciesla
KICP Colloquium - Joshua Frieman
3:30–5:00 pm ERC 161
Joshua Frieman (SLAC) will give the KICP Colloquium on 4/9 in ERC 161 and via Zoom.
KICP Seminar - William Luszczak
11:00 am–12:00 pm ERC 401
William Luszczak (OSU) will give the KICP Seminar at 11am on 4/10 in ERC 401 and via Zoom.
A&A Colloquium - Robyn Sanderson
3:30–5:00 pm ERC 161
Robyn Sanderson (Penn) will give the A&A colloquium on 4/16 at 3:30pm and via Zoom.
KICP Colloquium - Olivier Dore
3:30–5:00 pm ERC 161
Olivier Dore (JPL / Caltech) will give the KICP Colloquium on 4/23 in ERC 161 and via Zoom.
KICP Colloquium - Salman Habib
3:30–5:00 pm ERC 161
Salman Habib (ANL) will give the KICP Colloquium on 4/30 in ERC 161 and via Zoom.
A&A Colloquium - Brant Robertson
3:30–5:00 pm ERC 161
Brant Robertson (UC Santa Cruz) will give the A&A Colloquium on 5/7 in ERC 161 and via Zoom.