My team designed and built the CCD detector system for NEID, which provides high sensitivity and intrinsic thermal stability
at the sub-milli-Kelvin level. NEID means "to see" in the language of the Tohono O'odham, on whose land Kitt Peak National
Observatory sits. NEID is a new Precise Radial Velocity spectrometer for the U.S. user community that saw first light in 2019
and began regular science operations in 2020. NEID is designed for 30 cm/s radial velocity measurement precision, providing exciting
new capabilities for detecting and characterizing rocky exoplanets orbiting nearby stars.


My team built the MINERVA-Red spectrometer, a highly stabilized Precision Radial Velocity spectrometer optimized for
making observations of the closest low-mass stars to the sun through the 800 nm to 900 nm transmission window in our atmosphere.
MINERVA is an array of five robotic 0.7-meter telescopes at Mt. Hopkins, Arizona, designed for a wide range of exoplanet science
using photometric and spectroscopic techniques. MINERVA-Red relies on single-mode fibers and other "photonic" technologies to
enable an instrument that is very small in size and inexpensive, built mostly from "off the shelf" parts. MINERVA-Red was
commissioned in 2020. The MINERVA array also has instruments for photometric and spectroscopic observations at optical wavelengths.


My team built and demonstrated a prototype Oxyometer, a novel differential photometer designed to enable the detection
of molecules, such as oxygen, in the atmospheres of exoplanets transiting nearby, low-mass stars. We are currently working to use the
same technique with a small telescope to probe potassium in the atmospheres of hot Jupiter exoplanets.

Stellar Astrophysics at the Bottom of the Main Sequence

My team uses data from large surveys, like SDSS APOGEE, to study the structure and evolution of the smallest stars. We have
worked to characterize rotation, which is intimately linked to the evolution of stellar angular momentum, in a large sample of
low-mass stars using a new spectroscopic analysis technique that we developed. We have also carried out detailed measurements
of individual stellar systems to directly measure the physical properties of these stars to test theoretical models of stellar structure.

Telluric Absorption

My team has carried out several analyses of the impact of "telluric" water absorption features on ground-based
astronomical measurements and explored new approaches to making real-time measurements of the atmospheric water vapor
content using GPS-based and photometric techniques. We are also developing modeling frameworks that allow for detailed modeling
of telluric absorption features in high-resolution spectroscopic data, like that produced by NEID. Detailed modeling of telluric
absorption is emerging as an important challenge facing the next generation of Precise Radial Velocity spectrometers.

Oort Clouds

Working with my colleagues at Penn, my team and I have developed new strategies for detecting Oort clouds around other stars
using microwave emission maps from Cosmic Microwave Background surveys and placed interesting limits on the existence of
large clouds of icy bodies orbiting stars in the solar neighborhood. More than 60 years ago, Jan Oort proposed that the
outer reaches of our solar system, beyond 1000 AU, should contain a vast reservoir of cometary debris loosely bound to the sun.
Today, there is little direct evidence for the existence of this cloud, but measuring its properties would place interesting constraints
on models of solar system formation and evolution.