Ugochi Okeke
Research Mentor: Rachael Roettenbacher
Mentor Department: Astronomy, LSA
Author(s): Ugochi Okeke, Rachael Roettenbacher
Session: Session 4 (1:00 PM – 1:50 PM)
Presentation Type: Poster 136
Abstract
The Habitable Worlds Observatory (HWO) is an exoplanet focused NASA mission to observe and study the atmospheres of different exoplanets. Their goal is to detect signs of habitability on the exoplanets orbiting nearby stars. With improved stellar parameters, my work will help to identify potential habitable exoplanets ahead of the mission that will detect and characterize exoplanet atmospheres. This research project focuses on how optical interferometry can improve the measurement of fundamental stellar parameters of potential HWO targets to identify potentially habitable exoplanets. However, we run into difficulties categorizing which planets are habitable because of uncertainties from stellar parameters. For example, a small uncertainty in the measurements could artificially inflate a planet’s radius bigger than it actually is, which could incorrectly categorize the planet to be habitable or inhabitable. We aim to improve stellar parameters using optical interferometry to reduce the uncertainties and have the most precise stellar parameters possible, which will lead to the most precise planetary parameters. To achieve the most precise stellar parameters, we use optical interferometric data from the Center for High Angular Resolution Astronomy (CHARA) Array and the Very Large Telescope Interferometer. An interferometric array combines light from separated smaller telescopes to effectively make a telescope equivalent to the distance between the telescopes. One of the most important parameters is the angular diameter, the angular size of the star on the sky. We measure the angular diameters from the interferometry data then combine the angular diameter with other observations, which allows us to measure fundamental parameters like the mass, radius, rotation period, etc. To achieve this, I am creating a python program that measures the angular diameter and calculates the other fundamental parameters. I developed algorithms particularly for eta Cassiopeiae A, a potential target for HWO. The precise measurements from this project are contributing to a set of 42 potential HWO targets that are observable with these methods and will be included in a catalog of stellar parameters to evaluate the suitability for observations by HWO.
