Research

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Our solar system is the most observationally constrained planetary system known, and understanding its rich dynamical history will help us characterize the prevalence of, and requirements for solar system analogs and habitable planets around other stars. Classic models of the formation of the four terrestrial planets tend to form Earth-sized planets where Mars is today. If this were the case, Mars might very well look like Earth does today. I investigate why Mars' growth stalled; leaving it behind as a planetary runt.

Many aspects of Mercury starkly contrast the qualities of the other seven planets. In addition to being the smallest world, dynamically speaking, its' orbit is extremely isolated from that of its neighbor Venus. Moreover, Mercury's bulk composition is also unique. Unlike the small iron core's of Earth, Venus and Mars; Mercury's core comprises around three quarters of its total mass. I study the peculiar conditions that conspired to generate such a small, dense and isolated world.

While accretion, differentiation and geological processes have largely erased the record of the inner solar system’s earliest epochs on the terrestrial planets themselves, much of this lost information can be decoded from the precise study of the asteroid belt’s distinctive orbital, mass and compositional distributions. Moreover, the asteroid belt is quite sensitive to the particular dynamical behavior of the giant planets, and thus presents a useful constraint on the relative importance of giant planet migration in terrestrial planet formation. I use the detailed catalog of ~100,000 observed asteroids to derive useful constraints on solar system formation models.

Studying the early evolution of the solar system helps us better understand the Earth, and its overall place in the Universe. In this manner, models increasingly find that the inner solar system’s origins are intrinsically connected to the evolution of the giant planets. Studying how the giant planets affected the growing terrestrial worlds; namely the processes of giant planet growth orbital migration and instability provides us with insights into how these mechanisms might have sculpted the solar system’s planets differently than those of exoplanetary systems. I model the early dynamical evolution of the giant planets to understand the solar system's place within the larger constituency of planet systems in the cosmos.

The possibility of a new planet residing in the far reaches of the outer solar system has captivated the public over the last several years. The existence of the so-called Planet X is inferred via patterns in the orbital shapes of extreme trans-Neptunian objects (ETNOs). Much like the asteroid belt, a complex record of the solar system's earliest epochs is fossilized in the unique orbital distributions of these objects. I investigate the processes that placed these remote bodies on their present orbits, with an eye towards deriving useful constraints on the Planet X hypothesis.

The lack of planets inside Mercury’s orbit is another outstanding solar system puzzle. At least 30-50% of Sun-like stars host planets larger than Earths with orbital period shorter than Mercury's. While these "hot super-Earths" are common around other stars, observations suggest that Jupiter and Saturn analogs are rare. Furthermore, observed gas giant exoplanets typically inhabit orbits that are far more eccentric than those of Jupiter and Saturn. Bridging the gap between solar system science and the exoplanet catalog requires understanding whether the processes thought to have sculpted our system are the same as those that molded planets around other stars. In this manner, I am particularly interested in understanding whether habitable planets might emerge around the smallest, M-Dwarf stars.

My Ph.D. research culminated in a new evolutionary model for the terrestrial planets. Unlike other explanations for the low mass of Mars and the lack of planets in the asteroid belt, our model explains the entire solar system (both the terrestrial planets and the giant planets) in a single dynamical scenario.