Selected Publications
Signatures of Impact-driven Atmospheric Loss in Large Ensembles of Exoplanets
The results of large-scale exoplanet transit surveys indicate that the distribution of small planet radii is likely sculpted by atmospheric loss. Several possible physical mechanisms exist for this loss of primordial atmospheres, each of which produces a different set of observational signatures. In this study, we investigate the impact-driven mode of atmosphere loss via N-body simulations. We compare the results from giant impacts, at a demographic level, to results from another commonly invoked method of atmosphere loss, photoevaporation. Applying two different loss prescriptions to the same sets of planets, we then examine the resulting distributions of planets with retained primordial atmospheres. As a result of this comparison, we identify two new pathways toward discerning the dominant atmospheric-loss mechanism at work. Both of these pathways involve using transit multiplicity as a diagnostic, in examining the results of follow-up atmospheric and radial velocity surveys.
paired: A Statistical Framework for Detecting Stellar Binarity with Gaia RVs.
The effect of stellar multiplicity on the formation and evolution of planetary systems is uncertain, but
it is important to investigate given the prevalence of stellar multiples. At a demographic level, high-
resolution imaging and radial velocity observations indicate that planet formation is strongly disrupted
by close (< 10 AU) binaries while being relatively unaffected by wide (> 100 AU) companions. However,
the distance- and/or magnitude-limited nature of those surveys mean that large ranges of mass ratios
and separations remain largely unexplored. Data Release 3 (DR3) from the Gaia Mission includes
radial velocity measurements of over 6.5 million targets, which we employ to explore the effect of binary
companions within a statistical framework called paired. These companions present as a source of
excess radial velocity noise in the Gaia catalog, when compared to the typical noise for stars of similar
spectral type and magnitude. Within this framework, we examine the evidence for stellar multiplicity
among the stars surveyed by NASA’s Kepler and TESS missions. We use radial velocity information
published in Gaia DR3 to determine the presence of excess RV error and estimate the probability of
a spatially unresolved stellar companion for a large subset of the Kepler and TESS Input Catalog
stars. Where possible, we benchmark our inferred radial velocity semi-amplitudes against those from
ground-based radial velocity surveys. We determine that we are typically sensitive out to several AU
and mass ratios > 0.1, dependent upon the stellar magnitude. We aim for paired to be a useful
community tool for the exploration of the effects of binarity on planets at a population level, and for
efficient identification of false-positive transit candidates.