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Monday, March 24, 2025
4:00 PM - 5:00 PM
Cahill 370

Astronomy Tea Talk

The Influence of Elemental Abundances on Planet Formation and Structure / Eccentric mass transfer with self-consistent stellar evolution
Dr. Kiersten Boley, Hubble Postdoctoral Fellow, Carnegie EPL,
Kyle Akira Roche, Final-year PhD student, Northwestern University,

Speaker 1: Dr. Kiersten Boley

Title: The Influence of Elemental Abundances on Planet Formation and Structure

Abstract:

Planet formation is fundamentally linked to the chemical evolution of the galaxy. For planet formation to occur, there must first be sufficient metals within the protoplanetary disk. The growing number of planet discoveries reveals distinct planet populations, suggesting a diversity of compositions and formation mechanisms that arise from variations in initial conditions. As more data from spectroscopy surveys becomes available, we will be able to better constrain the influence of abundances on planet populations. I will discuss the impact of abundances on galactic planet formation through the lens of metallicity to determine the required material for the first generations of planets to form within the Milky Way. Using lava worlds as a case study, I will also show the potential impact of volatiles on the interior structure of rocky planets discussing whether we can expect all lava worlds to be inflated.

Speaker 2: Kyle Akira Roche

Title: Eccentric mass transfer with self-consistent stellar evolution

Abstract:

A majority of massive stars in binaries will interact with a companion at some point in their evolution through Roche-lobe overflow mass transfer (MT), giving rise to high-energy transients such as gravitational-wave sources, X-ray binaries, and exotic stellar populations. Modern binary evolution models simulate MT with self-consistent stellar evolution, but most focus exclusively on circular orbits. However, observations indicate that MT frequently occurs in binaries with significant orbital eccentricity, and some systems remain eccentric even after MT — challenging standard assumptions in binary evolution modeling. Eccentric MT represents an underexplored regime with profound implications for interpreting observed binary populations. In this talk, I present results from simulations integrating secular orbital evolution driven by eccentric MT into MESA, modeling systems with compact objects and non-degenerate donor stars. These simulations reveal novel evolutionary pathways and naturally produce populations of eccentric post-MT binaries. I will discuss the implications for observed binary populations and highlight future directions for incorporating eccentric MT into binary evolution theory.

For more information, please contact Raphael Skalidis or Steven A. Giacalone by email at skalidis@caltech.edu, giacalone@astro.caltech.edu.