Judah Van Zandt

Observational Astronomer
Image credit: ESO/L. Calçada
I'm a fourth-year astronomy PhD student at UCLA. I work with my advisor, Erik Petigura, to explore exoplanet occurrence and orbital characteristics. I am especially interested in combining multiple detection techniques to improve our understanding of exosystem structure.


I am interested in understanding the relationships between different objects that orbit stars. Some are planets, which can be small and rocky, or big and gaseous. Some are close to their host star, while others orbit far away. Some aren't planets at all, and instead fall into the category of "brown dwarfs." Some are even stars themselves!

The Distant Giants Survey

Two intriguing exoplanet classes have emerged over the last few decades: small and close-in, and big and far-out. What is the relationship between them? Do giant planets aid the formation of small rocky ones? Distant Giants aims to determine the  occurrence rate of large outer planets in systems where an inner small planet is already known to exist. The video above shows my 2022 GradSlam presentation, where I break down the Distant Giants Survey in just 3 minutes!

Image credit: wombo.art
Distant Giants Image

Partial Orbit Analysis

Planet characterization from partial orbits was motivated by the search for long-period planets in the Distant Giants survey. Planets on long orbits may produce signals over periods much greater than the observational baseline, revealing only partial orbits rather than fully-resolved Keplerians. To analyze these partial orbits, I developed Ethraid, a Python package which combines radial velocities, astrometry, and even direct imaging to achieve sensitivity to these outer companions. Ethraid is pip-installable, so you can use it to identify companions in your system of choice!