- Press Release
- September 25, 2023
Rocky Histories: The Effect Of High Excitations On The Formation Of Rocky Planets
Rocky planets both in and outside of our solar system are observed to have a range of core-mass fractions (CMFs).
Imperfect collisions can preferentially strip mantle material from a planet, changing its CMF, and are therefore thought to be the most likely cause of this observed CMF variation.
However, previous work that implements these collisions into N-body simulations of planet formation has struggled to reliably form high CMF super-Earths. In this work, we specify our initial conditions and simulation parameters to maximize the prevalence of high-energy, CMF-changing collisions in order to form planets with highly diverse CMFs.
High-energy collisions have a large vimp/vesc ratio, so we maximize this ratio by starting simulations with high-eccentricity and inclination disks to increase the difference in their orbital velocities, maximizing vimp. Additionally, we minimize vesc by starting with small embryos. The final planets undergo more high-energy, debris-producing collisions, and experience significant CMF change over their formation.
However, we find that a number of processes work together to average out the CMF of a planet over time, therefore we do not consistently form high-CMF, high mass planets. We do form high-CMF planets below 0.5 M⊕. Additionally, we find in these highly eccentric environments, loss of debris mass due to collisional grinding has a significant effect on final planet masses and CMFs, resulting in smaller planets and a higher average planet CMF. This work highlights the importance of improving measurements of high-density planets to better constrain their CMFs.
Jennifer Scora, Diana Valencia, Alessandro Morbidelli, Seth Jacobson
Comments: 19 pages. This is the version of the article before peer review or editing, as submitted to ApJ. This paper has been accepted to ApJ with some revisions
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2211.10491 [astro-ph.EP] (or arXiv:2211.10491v1 [astro-ph.EP] for this version)
From: Jennifer Scora
[v1] Fri, 18 Nov 2022 19:57:37 UTC (6,519 KB)