Overview

My research interests concern the origin and formation of planets. I’m fascinated with understanding how solar systems like our own form, and how planetary systems form and evolve generally. I observe circumstellar disks, which are pancakes of gas and dust that take shape around young stars as a result of the star formation process, and I use the properties of circumstellar disks as clues which I follow to reveal forming planets. I use big telescopes, special optics, and computer algorithms to peek inside the cradles of baby planets that orbit young stars. I also use smaller telescopes to observe young and low mass stars, leveraging a plethora of methods to understand the growth of adolescent stars. I love observational astronomy, and most of my work involves direct imaging, simulations of direct imaging, and the aggregation of direct imaging results.

In more technical terms, I use direct imaging detection methods to observe accreting protoplanets and circumstellar disks. My main focus is on transition disks, which are circumstellar disks which exhibit significant material and morphological evolution when compared to younger protoplanetary disks (transition disks boast wide gaps and striking spiral arms, and their dust and pebbles have evolved and drifted significantly). Transition disks are expected to be sites of active planet formation, and important high contrast observations within the past decade have supported this expectation.

A schematic of star and planet formation. Image credit: Elijah Spiro

There are a lot of contentious claims about planet formation and direct imaging, plenty of competing theories, and innumerable open questions, which is what makes the field so exciting. These kinds of studies also require methods and instruments which exist on the bleeding edge of astronomical and computational innovation.

Giant Accreting Protoplanets

Starlight obscures planets, which are much dimmer than their host stars. Our ability to resolve two sources of light is dependent on their distance between each other, our distance to the system, the wavelength of light we observe the system in, and the brightness of the two sources relative to each other. In nearly each of those dependencies, the physical limitations of the universe are stacked against observers resolving distant, dim, and close in exoplanets (i.e. exo-Earths or habitable planet analogs).

Another limiting factor is our ability to resolve sources through the distortion of Earth’s atmosphere. In order to combat this, astronomers use deform-able mirrors to cancel out the disortion of the atmosphere. This technique is referred to as “adaptive-optics” (AO). There’s a great online resource on adaptive optics written by a professor at RIT here. I’ve included some cool explainer images in the gallery below as well.

A good analogy to help understand this problem goes something like ‘trying to image a Jupiter sized planet around a sun-like star is like trying to take a picture of a firefly next to a lighthouse from across the continental USA.’ But, strangely enough, this isn’t impossible.

Now imagine the lighthouse is 300+ light years away from you. Image credit: NASA Space Place

I use some very clever tricks, developed by people much smarter than I, to remove starlight from adaptive optics images in a process referred to as “PSF subtraction.” I use angular differential imaging (ADI), leveraging the rotational diversity of a time series of observations and spectral differential imaging (SDI), leveraging the excess luminosity exhibited by objects undergoing accretion (which releases a massive amount of energy) to remove starlight from images via the python implementation of the fancy sounding Karhunen-Loeve Image Processing (pyKLIP). Another analogy: I essentially use a form of facial recognition to create a model of the host star, which I subtract from images to reveal hidden planets. I this work under the tutelage of Kate Follette, who is the PI of the Giant Accreting Protoplanet Survey (GAPlanetS).

This image visualizes the SDI technique I employ to observe accreting planets. While starlight and the distortions caused by the atmosphere are equal brightness between the two wavelengths of light, the accretion signal from the giant planet is brighter in an emission band characteristic of Hydrogen. By subtracting the two images, astronomers can isolate the signal from the growth of the young planet. Pictured is the giant, accreting planet LkCa 15b, which was discovered by my undergraduate advisor Kate Follette. Image credit: Follette Lab

After uncovering planet signal using adaptive optics, angular and spectral differential imaging, and the KLIP principle component analysis algorithm, I use a pyKLIP forward modeling technique to determine the position and brightness of planets. This allows for a more nuanced understanding of their properties, evolutionary history, and how they shape the environment of their host transition disks.

This image shows the ADI+SDI reduction of beta Pictoris b, a Jupiter sized exoplanet, and the model of that image. The model is a great fit, because the residual map (data-model) on the far left is essentially featureless. I use the same modeling technique, albeit on a different target system. Image credit: Wang et al. 2016

Simulating Exozodi Yield

During the summer of 2020 (amid other things) I worked remotely with Dmitry Savranski in the Space Imaging and Optical Systems Lab (SIOS Lab) at Cornell University. I used EXOSIMS, a direct imaging simulation suite developed by SIOS lab, to predict the yield of the miniaturized Distributed Occulting Telescope (mDOT), a novel cubesat proposed by some very smart people at Stanford University which will demonstrate the effectiveness of an occulting star shade in negating starlight to observe exoplanets and circumstellar dust. You can view slides from a presentation I gave on this research here.

Transition Disk Database

The Transition Disk Database (TDD) is an aggregation of transition disk morphology and properties. I presented the results of this literature review at AAS 235 (see my poster here).

This is a picture of me presenting my poster on the TDD at the 235th meeting of the AAS in Honolulu, HI. Nice shirt, too!

Very Low Mass Variability

I observed VLM stars using the HDI on the WIYN 0.9m telescope atop Kitt Peak National Observatory on the Tohono O’odham Nation. I presented some of this research with my collaborator Lena Treiber to the Five College Astronomy Department (who paid for my trip to KPNO), you can see our beautiful poster and some very beautiful images of the Taurus star forming cloud below.

Teaching Assistance and Star Clusters

I work as a TA for many of the astronomy course offerings at Amherst College (ASTR 112: Alien Worlds, ASTR 337: Observational Techniques I, and ASTR 341: Obs. Tech. II). I set up and operate the 11in Cassegrain telescopes atop the New Science Center’s observatory, working under one of the coolest people I know, Sarah Betti. We’ve gotten some pretty good data, given our local weather conditions and elevation, which I’ve used to fit isochrones to open clusters and image pre-main-sequence stars.