I did my PhD at the Center for Astrophysics | Harvard & Smithsonian studying the atmospheres of large exoplanets and writing software to help analyze them. I had the opportunity to work on all stages of the process, including observing with large ground-based observatories, extracting and reducing time series of raw spectral data, detrending of potential signals via different Gaussian Process (GP) and Principal Component Analysis (PCA) techniques, and model fitting with a range of statistical Bayesian inference frameworks including Markov Chain Monte Carlo (MCMC) and nested sampling to study the atmospheres of these other worlds.
I currently serve as an education and outreach astronomer for the Carl Sagan Center for Research at SETI. In my free time, I like to row on Lake Merritt, help maintain JuliaAstro and other open source projects, and help run Onaketa: an education non-profit dedicated to supporting Black and Brown youth in STEM.
A pure Julia implementation of astroalign to efficiently align astronomical images via asterism matching when available. This circumvents the expensive step of initially WCS plate solving your images. [GitHub][Notebook]
Tutor-student matching
This tool automatically downloads, extracts, and post-processes schedule availabilities from WhenIsGood responses to display the intersections between available dates/times for all tutor-mentor / student combinations. A handy tooltip also displays the overlapping times for a given tutor-mentor / student pair, which is automatically copied to the clipboard at the click of a mouse. [GitHub]
Exoplanet locator
A groovy exoplanet sky chart created with data queried from the exoplanet archive, bright star locations from the Hipparcos, Yale Bright Star, Gliese (HYG) database, and asterisms from the Stellarium public repo. [GitHub][Notebook]
System parameters calculator
Self-consistent computations of exoplanet parameters from stellar and orbital observations. Useful for estimating the potential observability of an exoplanet's atmopshere. [GitHub][Notebook]
Orbital trajectories
Integrated orbit of a hypothetical three-body star-planet-moon system via s=2 Adams-Moulton method. This is motivated by the first potential discovery of an exomoon made not too long ago. [GitHub][Notebook]
Population dynamics
The same integration method applied to the Lotka–Volterra system of differential equations describing population growth. [GitHub][Notebook]
Artificial energy loss
Particle stream trajectory in a binary Roche Potential with artificial energy loss every time step to mimic the energy that is lost to shocks and other collisions in real fluid interactions. This was done by having the test particle lose energy while maintaining its angular momentum. I also added a little kick in the z component of the particle's initial velocity to make it a little more fun to watch. [GitHub]
WASP-12/b system
Top-down view of the same code applied to WASP-12/b (to scale). I waited until a full orbit to turn on the artificial energy loss to mimic one full lap of the accretion stream before colliding with itself. The corners due to the Coriolis force are clearly seen and the orbit settles down into its circularization radius (in green), as predicted from angular momentum conservation. [GitHub]
WASP-12/b 2D
An analog to the toy-model from the particle trajectory code above. I replaced the massless test particle in that code with a fluid outflow boundary, following properties adopted from Lai et al. (2010). I then added an artificial ramp up in density at around the 5 day mark to effectively fast-forward the disk to a more evolved state.
WASP-12/b 3D
I adapted the hydro simulation to 3D to create the image above. This is an isodensity contour plot taken partway through the simulation. The location of L1 can be seen as the orange-yellow sphere towards the bottom left. These simulations were used to create virtual light curves to compare with observations from HST's Cosmic Origins Spectrograph.
WASP-50b (Weaver et al. submitted)
We present a new ground-based visual transmission spectrum of the hot Jupiter WASP-43b, obtained as part of ACCESS. We collected four transits observed between 2015 and 2018, with a combined wavelength coverage between 5300 and 9000 Å and an average photometric precision of 708 ppm in 230 Å bins. We perform an atmospheric retrieval of our transmission spectrum combined with literature Hubble Space Telescope/WFC3 observations to search for the presence of clouds/hazes as well as Na, K, Hα, and H₂O planetary absorption and stellar spot contamination. We do not detect a statistically significant presence of Na I or K I alkali lines, or Hα in the atmosphere of WASP-43b. We find that the observed transmission spectrum can be best explained by a combination of heterogeneities on the photosphere of the host star and a clear planetary atmosphere with water. [GitHub][Notebook]
HAT-P-23b (Weaver et al. 2021)
We present a new ground-based visible transmission spectrum of the high-gravity, hot Jupiter HAT-P-23b, obtained as part of the ACCESS project. We derive the spectrum from five transits observed between 2016 and 2018, with combined wavelength coverage between 5200 Å - 9269 Å in 200 Å bins, and with a median precision of 247 ppm per bin. HAT-P-23b's relatively high surface gravity (g ~ 30 m/s²), combined with updated stellar and planetary parameters from Gaia DR2, gives a 5-scale-height signal of 384 ppm for a hydrogen-dominated atmosphere. Bayesian models favor a clear atmosphere for the planet with the tentative presence of TiO, after simultaneously modeling stellar contamination, using spots parameter constraints from photometry. If confirmed, HAT-P-23b would be the first example of a high-gravity gas giant with a clear atmosphere observed in transmission at optical/NIR wavelengths; therefore, we recommend expanding observations to the UV and IR to confirm our results and further characterize this planet. This result demonstrates how combining transmission spectroscopy of exoplanet atmospheres with long-term photometric monitoring of the host stars can help disentangle the exoplanet and stellar activity signals. [GitHub][Notebook]
WASP-43b (Weaver et al. 2020)
We present a new ground-based visual transmission spectrum of the hot Jupiter WASP-43b, obtained as part of ACCESS. We collected four transits observed between 2015 and 2018, with a combined wavelength coverage between 5300 and 9000 Å and an average photometric precision of 708 ppm in 230 Å bins. We perform an atmospheric retrieval of our transmission spectrum combined with literature Hubble Space Telescope/WFC3 observations to search for the presence of clouds/hazes as well as Na, K, Hα, and H₂O planetary absorption and stellar spot contamination. We do not detect a statistically significant presence of Na I or K I alkali lines, or Hα in the atmosphere of WASP-43b. We find that the observed transmission spectrum can be best explained by a combination of heterogeneities on the photosphere of the host star and a clear planetary atmosphere with water. [GitHub]
