TRAPPIST-1 is a nearby ultra-cool dwarf that is host to a remarkable planetary system consisting of seven transiting planets. The orbital properties and radii of the planets have been well-constrained, and recently the masses of the inner six planets have been measured with additional ground and space-based photometric observations. Large uncertainties in these mass measurements have prevented a robust analysis of the planetary compositions. Here we perform many thousands of N-body dynamical simulations with planet properties perturbed from the observed values and identify those that are stable for millions of years. This allows us to identify self-consistent orbital solutions that can be used in future studies. From our range of dynamical masses, we find that most of the planets are consistent with an Earth-like composition, where TRAPPIST-1f is likely to have a volatile-rich envelope.
@article{arxiv.1704.02261,
title = {Plausible Compositions of the Seven TRAPPIST-1 Planets Using Long-term Dynamical Simulations},
author = {Billy Quarles and Elisa V. Quintana and Eric D. Lopez and Joshua E. Schlieder and Thomas Barclay},
journal= {arXiv preprint arXiv:1704.02261},
year = {2017}
}
Comments
4 pages, 2 figure, 3 tables, accepted to ApJL; Changes made due to first review including modification and addition of figures