February 17, 2023

The ExoExplorer Science Series presents talks by cohort members Armaan Goyal (Indiana U) & Alison Duck (Ohio State) on Feb 17, 2023, from 11 AM - 12 PM Pacific / 2 PM - 3 PM Eastern. Connection information is below.

Speaker: Armaan Goyal (Indiana U)

Title: The Interplay of Mean Motion Resonance and Peas-in-a-Pod Architectures

Abstract: Planets orbiting the same star tend to display a striking degree of uniformity in their size, mass, and orbital spacing, exhibiting a “peas-in-a-pod” phenomenon that serves to place invaluable constraints on the formation of multiple-planet systems. In this talk, I shall discuss a pair of statistical analyses that probe the relationship between mean motion resonance (MMR) and the emergence of these peas-in-a-pod architectures. Recent demonstrations of planetary mass uniformity have largely been limited to systems that exhibit strong transit-timing variations (TTVs), and are thus near MMR. Accordingly, I shall present in the first half of this talk a novel demonstration of mass uniformity for a sample of planetary systems entirely devoid of TTVs, suggesting that peas-in-a-pod architectures indeed persist for non-resonant systems as well. While this result may seem to imply that the emergence of peas-in-a-pod architectures occurs agnostically with regard to resonance, the question still remains if the degree of the associated planetary uniformity differs between near-resonant and non-resonant configurations. I shall thus present in the second half of this talk a direct comparison of size uniformity between the two modes, finding that near-resonant planetary configurations display enhanced size uniformity compared to their non-resonant counterparts, both across entire systems and within the same planetary system. These results are broadly consistent with a variety of formation paradigms for multiple-planet systems, though further investigation is necessary to ascertain whether the respective evolutionary channels for non-resonant and near-resonant configurations comprise a singular process or are themselves wholly distinct.

Speaker: Alison Duck (Ohio State)

Title: Reanalyzing Kelt-15b: An Exploration of Systematic Errors in Transiting Planets and Their Host Stars

Abstract: Transiting planet systems offer the best opportunity to measure the masses and radii of a large sample of planets and their host stars. However, relative photometry and radial velocity measurements alone only constrain the density of the host star. Thus, there is a one-parameter degeneracy in the mass and radius of the host star, and by extension the planet. Several theoretical, semi-empirical, and nearly empirical methods have been used to break this degeneracy and independently measure the mass and radius of the host star and planets(s). We focus our analysis on modelling KELT-15b, a fairly typical hot Jupiter, using each of these methods implemented in EXOFASTv2. As we approach an era of few percent precisions on some of these properties, it is critical to assess whether these different methods are providing accuracies that are of the same order, or better than, the stated statistical precisions. We investigate the differences in the planet parameter estimates inferred when using the Torres empirical relations, YY isochrones, MIST isochrones, and a nearly-direct empirical measurement of the radius of the host star using its spectral energy distribution, effective temperature, and Gaia parallax.

Meeting link:
Meeting number:
2763 643 6746