Date

2018

Department or Program

Astrophysics

Primary Wellesley Thesis Advisor

Wesley Watters

Additional Advisor(s)

David Latham

Additional Advisor

Andrew Vanderburg

Additional Advisor

Allyson Bieryla

Abstract

The discovery of planets outside of our own solar system has captured the imagination of scientists and the public alike. In just the past decade, more than 3000 planets have been discovered with the groundbreaking NASA telescope missions Kepler and its successor, K2. In just three years, the K2 mission has yielded some remarkable results, with the discovery of over 300 confirmed planets and 480 reported planet candidates to be validated. The K2 mission detects planets by recording any periodic dimming in stars; this dimming often indicates that a planet is in orbit around the star, blocking a portion of its light. A major challenge with the analysis of these data is to identify planets in star-crowded regions, where individual camera pixels overlap multiple stars.

In this thesis, I developed, tested, and evaluated a validation process for ruling out false-positive detections of planets in K2 observations of star-crowded regions. Using Markov chain Monte Carlo analysis, I fitted a model to obtain the transit parameters for each candidate planetary system. Later, I used seeing-limited on/off imaging to rule out false positives due to nearby transiting binary star systems. These results were then evaluated using a software program called validation of exoplanet signals using a probabilistic algorithm (VESPA) to estimate the probability of a false-positive detection. Such techniques and results are important tools for conducting candidate validation and follow-up observations for space-based missions, including the upcoming Transiting Exoplanet Survey Satellite (TESS) mission, since its large camera pixels resemble K2 star-crowded fields.

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