Research
JWST Transmission Spectroscopy of Young Sub-Neptunes
I currently work with Dr. Adina Feinstein to investigate the composition of young sub-Neptunes around active host stars. By performing joint fits of these planet’s transits and sources of stellar activity, we can derive more accurate transmission spectra of these gas giants, probe planetary formation mechanisms, and gain insight into properties of the host star.
ASAS-SN
(All-Sky Automated Survey for Supernovae)
From May 2023 – August 2025, I performed daily quality control of data obtained by 20 ASAS-SN telescopes to visually inspect images for quality control, verify supernova and other transient candidates by inspecting the images obtained from that position the sky, and release of confirmed ASAS-SN discoveries to the public.
Long Term Variability
From May 2023-August 2025, I worked with Dr. Chris Kochanek to search for stars exhibiting long term variability using a decade of ASAS-SN’s optical data. Starting with over 14 million sources, I fit the seasonal medians brightnesses of stars as linear or quadratic trends then identified and discarded false positives. I found 1208 candidates, of which 575 were previously misclassified variables in other catalogs and 633 were new variables. The previously flagged systems had a range of odd or vague classifications because this long time scale variability does not fit into a standard class. The sources are scattered on a CMD and exhibit different behaviors. Some of the variability is striking, with nearly an order of magnitude, slow brightness changes over a decade. Matching to WISE, some of the variability is due to changes in dust obscuration, and some is not. This is the first survey for this kind of variability.
Final candidates with 14.5 < g < 15 magnitude can be found here!
(see Petz&Kochanek+2025 for candidates with 13 < g < 14.5 magnitude)
Exoplanet Atmospheres with High Resolution Spectroscopy
From May 2022 – August 2025, I worked with Dr. Marshall Johnson at the Ohio State University to explore the atmospheric chemistry of ultra hot Jupiters (UHJs).
Using emission spectroscopy from the PEPSI spectrograph of the Large Binocular Telescope and atmospheric modeling, we assessed the detectability of 68 different atomic and molecular species in UHJ KELT-20b, as well confirm or dispute previous detections of species made in literature. We confirmed the presence of Fe I, made a tentative detection of Ni I, and refuted previous claims for the detections of other species.
We also investigated the atmospheres of the UHJs TOI-1431b and TOI-1518b with the first ever high resolution emission spectroscopy observations for these planets. We determined the atomic and molecular species present, detecting several atomic species and tentatively detecting others in both planets. Notably, we find Fe I in both planets, which appears to confirm that this species is ubiquitous in UHJs with temperature inversions. Through a HJ population analysis, I found that models with TiO more closely match the zone in which these planets’ atmospheres begin to become inverted. However, this is challenged by lack of TiO detections in these planets, further pointing to Fe I as a large thermal inversion agent in this population.
Young Stellar Objects
In the summer of 2021, I worked with Dr. Adam Ginsburg at the University of Florida to constrain the properties of young stellar objects. I fit synthetic spectral energy distributions to the optical and infrared fluxes of young stellar objects in the infrared dark cloud G351.77 to constrain properties such as the stellar temperature, radius, luminosity, disk mass, and viewing geometry.