Date of Award

Spring 2006

Document Type

Restricted Thesis

Terms of Use

© 2006 Saurav Dhital. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Physics & Astronomy Department

First Advisor

Eric L.N. Jensen


Most close binary T Tauri stars are surrounded by circumbinary disks similar to the protoplanetary disks seen around young single stars. In the case of binaries, however, theory predicts that the time-varying gravitational perturbations of the disk from an eccentric binary should cause the accretion to vary in time with the binary orbit. Such pulsed accretion may be visible as periodic photometric variations. We report the photometric monitoring of the young spectroscopic binary UZ Tau E conducted during 2004-05 and 2005-06 seasons using the 0.6-m Perkin Telescope at Wesleyan University. The brightness of the system was found to vary periodically with an amplitude of 0.6 magnitudes and at the orbital period of ~ 19 days. This periodicity is especially pronounced in the first season. The light curve of UZ Tau E shows a broad peak at orbital phase of 0.6-0.8, consistent with predictions by Artymowicz and Lubow (1996) for a binary system with a low orbital eccentricity. Our observations for the first season match accretion rate onto the secondary star (as calculated by Artymowicz and Lubow (1996) more closely leading us to think that the primary might have been hidden to us. Similar variations have been seen in DQ Tau for the high-eccentricity case (Mathieu et al. 1997) but not for another high-eccentricity system, AK Sco (Alencar et al. 2003). We think the higher luminosity and age of AK Sco along with its larger stochastic variability might be a reason for the apparent absence of periodicity. Our findings support the theoretical prediction that material can stream across the gap between circumbinary and circumstellar disks in a binary system, potentially lengthening the planet-forming timescale in such systems.