Graduate student Armaan Goyal, working with Songhu Wang, is exploring the architectures of exoplanet systems. Planets orbiting a given star are often strikingly similar in size and mass, and their distances from the host star are also spaced evenly. Since this “peas-in-a-pod” setup is very different from what we see in our own solar system, Armaan is interested in the following questions: Why this trend is so common? What may this tell us about how planetary systems form in general?
His research compares this peas-in-a-pod appearance across two main groups of planetary systems. The first group are systems in which planets are near resonance, where the planets themselves have orbits with periods that form very simple fractions (e.g. an outer planet might orbit twice in the time it takes an inner planet to orbit three times). The second group are systems whose planetary orbits are not synced like this, and are therefore not resonant. While both types of exoplanet systems seem to generally follow the peas-in-a-pod trend, the planets in a near-resonant system are usually more similar to each other than the planets in a non-resonant system. Armaan wants to understand whether near-resonant and non-resonant exoplanet systems form in similar or different ways.
Armaan is presenting his work to other researchers as part of the NASA ExoExplorers program. His presentation will be available on the ExoExplorers website at the link below.