I'm currently a third year graduate student in the Astronomy
Department at the University of Washington, where I study
systems with one star, two stars, red stars, and blue stars. I work with
Professors Emily Levesque and Suzanne Hawley and I am primarily interested
in determining the ages and other fundamental properties of stars in our Galaxy.
I graduated from
Boston University, where my research interests included low-mass
stars, binary systems, and particle simulations of PET and
ultrasound scanners at CERN. My CV is available here.
The ability to estimate the ages of stars is a crucial step in understanding the evolution of stellar, Galactic and planetary phenomena. My latest work is focused on calibrating gyrochronology, an empirical method of determining stellar age that relies on the color and rotation period of a star (rotation rate offers direct insight into the evolution of stellar angular momentum and decreases with stellar age). However, given that stellar rotation periods are most often measured from star spot modulations and resulting brightness variations, this is a time-intensive task and the dimmer, older, and less active stars (with fewer or no spots) have been difficult to characterize.
Fortunately, the Kepler spacecraft monitored over 200,000 stars with nearly uninterrupted, high-precision photometry and has thus provided an unprecedented platform for stellar research. As an undergraduate, I identified over 500 stellar binaries with time-series data from Kepler and measured stellar rotation periods to calibrate gyrochronology models and develop more accurate methods of determining stellar ages (xkcd-ified work here). We can also use this method to extrapolate the ages of attending planetary systems (talk and poster). I currently use UW's time at Apache Point Observatory to spectroscopically confirm these binaries and further investigate their magnetic activity levels and metallicities.
M dwarfs are stars much smaller, dimmer and less massive than the Sun, constitute ~75% of the stars in our Galaxy, and are the most abundant hosts of terrestrial planets. I'm particularly interested in studying the rotation and magnetic activity of M dwarfs to develop better methods of determining the ages of low-mass stars and their attending planets (paper and poster). Given that M dwarfs are ubiquitous in the Milky Way, we can also use them as test particles to investigate how stellar age varies in and contributes to Galactic structure.
Eclipsing binary stars (EBs) provide accurate measurements of stellar mass and radius and therefore play a critical role in constraining stellar evolution models. Working with Suzanne Hawley, I use Kepler photometry, spectroscopic data from Apache Point, and the eclipsing binary modeling package JKTEBOP to characterize these systems (poster).
Outreach & Teaching
Amidst the recent Star Wars frenzy, I taught local beer enthusiasts How to Find a Tatooine at Astronomy on Tap Seattle.
The UW Pre-Major in Astronomy Program (Pre-MAP) is an undergraduate
program designed to increase and retain students from traditionally
underrepresented groups in STEM fields by engaging freshmen in research and establishing a supportive network of peers and
advisors. I co-mentored (with John Lurie, Jim
Davenport, and Suzanne Hawley) two students in Fall 2015 to
characterize the orbital dynamics of eclipsing binaries (Tricycle).
At UW, I've been a teaching assistant for two undergraduate courses: Introduction to Astronomy and Planets. While at Boston University, I was an undergraduate teaching assistant for Alien Worlds, a course focused on the search and characterization of planets outside of our Solar System (exoplanets). I also helped to develop one of BU's first massive open online courses (Alien Worlds MOOC).
University of Washington
Phone: (206) 616 - 1505
Email: kweis (at) uw (dot) edu
Office: Physics and Astronomy Building (PAB) B335