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Research:

I combine observations and models to understand the atmospheres of planets, exoplanets, brown dwarfs, and stars. You can download my CV here.

Recent Work

Brown Dwarfs Irradiated by White Dwarfs: Analogues for Hot and Ultra-hot Jupiters

We investigate the unique atmospheres of short-period brown dwarfs that experience the intense UV irradiation of white dwarf hosts. Using self-consistent and retrieval models, we explore how these objects are both similar and distinct from their lower-mass exoplanet cousins.

UV Transit Spectral Features as Probes of Metals and Rainout

We explore how atomic metals and molecules like SiO shape the short-wavelength transit spectrum of hot Jupiters. When we include a comprehensive list of opacity sources, we can explain the large UV and blue transit depths of several ultra-hot Jupiters.

PETRA: The PHOENIX Exoplanet Retrieval Algorithm

We developed a retrieval framework around the widely-used and well-tested PHOENIX atmosphere model. PETRA is capable of retrieving atmospheric properties from observations of all kinds of sub-stellar and stellar objects.

How do ultra-hot Jupiters vary between host stars?

We find that ultra-hot Jupiters around early-type host stars will have much larger temperature inversions compared to planets around later-type host stars. We also futher quantify which species are heating up ultra-hot Jupiter atmospheres (Spoiler: its neutral and singly-ionized iron!). ADS

What are the atmospheres of ultra-hot Jupiters like?

Jovian planets exceeding 2000K begin to exhibit some properties only seen in stars (e.g., H- opacity). We present some of the first fully self-consistent models of these hot planets, including KELT-9b at ~4500 K. We find that inversions in these planets will be common, regardless of the presence of TiO and VO. ADS

The HST/STIS optical transmission spectrum of warm-Neptune GJ 436b.

We observed GJ 436b, a JWST GTO target, with HST/STIS. The planet's spectrum is consistent with NIR observations implying a cloudy or high metallicity atmosphere. We find an unexplained jump in the transit spectrum at 0.8 microns in the transit spectrum of several sub-Jovian exoplanets. We also measure the host stars rotation period and activity cycle. ADS

Three isotopes of CO in a M-dwarf binary indicate SNe enrichment.

In a study led by Prof. Ian Crossfield, we measured 12C16O, 13C16O, and 12C18O in GJ 745AB. The resulting isotopic ratios suggest the binary was significantly enriched by a nearby core-collapse supernovae. I constructed the stellar atmosphere models for the isotopic detections and measurements. ADS