Catherine Slaughter, M.Sc.

Astrophysicist | Scicomm Enthusiast
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Descriptions of current research projects and ongoing research interests.
An extended list of past significant research projects can be found on my projects page.


In general, my research interests are in small things–on an astrophysical scale, that is. Star clusters, stars, planets, moons, dust, gas, etc. In particular, I find myself drawn to “weird” stars and stellar systems. I am curious about stars that differ in some way from our typical understanding of stellar processes. This includes (but is far from limited to) transient events that cannot be modeled 1-dimensionally, complex orbital physics, system (planetary and/or multistellar) co-evolution, RR Lyrae stars, very metal poor stars, ULXs, high-energy binary systems, late-stage evolutionary phases, etc.

As for research methodology, I would generally consider myself interested in observational astronomy with computational applications, or vice-versa. This includes using new algorithmic methods to better analyze observational data, modeling systems for comparison with observational data, etc.

Ph.D. Research

While I am still in a bit of a discovery phase with my Ph.D. reserach project, I know I am using HST (and, eventually, JWST) archival data to study RR Lyrae stars in nearby dwarf galaxies. I am advised by Prof. Evan Skillman at MIfA and Prof. Dan Weisz at UC Berkeley.

Master’s Thesis Research

My Master’s thesis is currently being conducted under the supervision of Prof. Matthew Kenworthy at Sterrewacht Leiden, where I am using computational and modeling methods to attempt to recreate an observed lightcurve around ASASSN-21qj, believed to be the result of a planetesimal collision. This project comes in two main parts. First, using keplerian orbital mechanics, I have created a simulation of a spherical planetesimal “explosion,” and an associated light curve from the resulting cloud. This light curve is a linear combination of a set of (hopefully) basically orthogonal light curves, where each sub-curve is associated with the material of a given initial velocity kick. The second part of the project focuses on taking the real ASASSN-21qj data, and fitting the set of model light sub-curves to it in a linear combination. In this case, the combination constant for each light curve represents the relative amount of mass which was blown out at the given sub-curve’s associated velocity in the explosion. Results are forthcoming.

First-Year Master’s Research

My first-year research project for my Master’s was conducted under the guidance of Prof. Xander Tielens and Dr. Cornelia Pabst at Sterrewacht Leiden. Inspired by the work of Dr. Bob O’Dell (O’Dell et al. 2017), I was studying velocity structures and bubbles in the Greateer Orion Nebula Region. I used SOFIA and Herschel data and a radiation field simulation code developed by Ramsey Karim at the University of Maryland to develop a new method for identifying regions of interest in the search for such velocity structures. By removing Theta 1 Ori C, the brightest star in the Trapezium cluster, from the simulated radiation field map and comparing to the complete map, I identified regions where local radiation dominated. I was able to conclude that this method was sucessful in identifying regions where these bubble structures exist. I found further evidence for the existence of a secondary bubble surrounding Theta 2 Ori A in the Veil region, as well as identifying a previously undiscussed fossil bubble structure around HD37150 in OMC A.

Culminating Undergraduate Research

At Dartmouth, all my resarch lead up to my culminating undergraduate experience, advised by Prof. Brian Chaboyer. The Chaboyer Group at Dartmouth College focuses on research in stellar evolution. In particular, the group helps maintain and calibrate DSED evolution models, and uses the database to study stellar population formation of the Milky Way, satellite galaxies, globular clusters, etc.

The purpose of my project was to estimate the ages of several globular clusters in the Milky Way. These clusters contain the oldest stars in the galaxy, and determining the age of them provides a strict lower limit on the overall age of the universe. In order to do this, I am implementing a Monte-Carlo Main Sequence Fitting method using DSED models and Gaia parallax data, as done in O’Malley et al. 2017, to find my age estimate. I can further reduce the error in this value using numerical analysis methods as outlined in Dolphin 2001. This method looks at the number densities of stars in the cluster at certain places in their evolution. In particular, I’ll be looking at stars at and just beyond the main sequence turnoff, because evolution occurs much more quickly starting at this point. This project utilizes Gaia parallax distance data, and error can be further reduced with the release of Gaia DR3.

The limit estimated will be useful in further research related to the Hubble Tension—a discrepancy in experimental findings which can estimate the age of the universe. The value for the age of the universe impacts what we know about cosmology going all the way back to the Big Bang, and is essential to the cosmological standard model. Because the distances to the clusters studied can be found via parallax, the value obtained in this project will not be impacted by potential error in the distance ladder. The lower limit estimated will serve as a useful boundary condition in studying the Hubble Tension.