I study transiting exoplanets and their host stars.
My work centers on finding and characterizing transiting exoplanets. I'm primarily interested in small exoplanets around nearby small stars that afford the best opportunities for detailed atmospheric studies, including searches for biosignatures in the near future. I'm interested in stellar activity in these same systems, and I work a lot on new approaches for constraining stellar photospheric heterogeneity and disentangling stellar and planetary signals in transmission spectra.
I work with some great teams to find small planets transiting small stars, including SPECULOOS, Project EDEN, and TESS. In particular, I've had the pleasure of contributing significantly to the discoveries of K2-315b, an Earth-sized planet transiting an M3.5 dwarf at 57 pc, and TOI-2406b, a sub-Neptune transiting a thick-disk M4 dwarf at 56 pc. Both are among the best known targets for atmospheric studies.
Stars and faculae can mimic or mask planetary spectral features in exoplanet transmission spectra. During my PhD, I examined the typical scale of this "transit light source" effect and found this is a concern for essentially all M-dwarf systems and many active G- or K-dwarf systems.
As a postdoc, I'm interested in new approaches to constraining the properties of exoplanet host stars and mitigating this effect. I recently co-led Study Analysis Group 21 of NASA's ExoPAG, which focused on the impact of the TLS effect on precise, space-based transmission spectra. Over the course of 18 months, this interdisciplinary group of >100 scientists identified 14 needs that can be addressed in the coming years to better constrain host-star photospheres and make the most of precise transmission spectra. These feed into seven overarching science questions, which are summarized below and detailed in full in our final report.
Keeping in mind stellar impacts, I'm ultimately interested in studying exoplanet atmospheres, particularly in transmission, which affords us the greatest opportunity today to study small, temperate worlds. To this effect, I use HST and JWST, and I am a founding member of Project ACCESS, which is conducting a large, ground-based transmission spectroscopy survey with the 6.5-m Magellan Telescopes. To date, we've published optical transmission spectra of nine targets, including the sub-Neptune GJ1214 and the ultrahot Jupiters WASP-19b and WASP-103b. In all three of these studies, we infer the presence of unocculted photospheric heterogeneities (i.e., spots and faculae) that alter the observed transit depths, underscoring the importance of constraining stellar photospheres in order to enable unbiased studies of the planetary atmospheres.