Twinkle, Twinkle, Tiny Exoplanet—SMC’s Brian Hill Joins NASA Project

Assistant Professor Brian Hill conducts research at SMC's observatory.On a hilltop behind campus stands the Geissberger Observatory. Though the outside might not seem imposing, what lies within is impressive—as is the project Assistant Professor of Physics & Astronomy Brian Hill and his students have taken on with the MIT–led NASA mission, Transiting Exoplanet Survey Satellite (TESS).

This last summer, Hill worked with engineering major Ariana Hofelmann to make improvements to the observatory. After successfully completing their planned improvements, they applied to the TESS Follow-up Observing Program (TFOP). TESS aims to discover thousands of exoplanets—which are planets orbiting stars outside our solar system. Hill and Hofelmann were accepted into the TFOP subgroup, which consists of a large network of observers that will help confirm or invalidate candidates identified by TESS.

“We are incredibly fortunate that the TESS collaboration has created a path for observatories like ours to do ground-based follow-up on the new exoplanets it is finding,” said Hill.

The TESS Satellite launched from Cape Canaveral, Fla., on April 18 of this year. “The objective of TESS is to scan the universe for exoplanets,” wrote Hofelmann in her summer project report. “TESS will identify these systems by taking images of stars and searching for drops in their light output, an indication that a planet has crossed the star. However, because of the large field of view of the TESS cameras (the area of the sky the camera takes an image of) there could be up to 10 stars covered by each pixel of the camera. This means that the images from the satellite will indicate the approximate area where a transit has occurred but not the exact star around which a planet orbits.”

After TESS identifies a candidate, the TFOP network of observatories and researchers examines it to confirm or invalidate whether a star has an exoplanet eclipsing it. Here at SMC, to tune up for this work, a 115mm Stellarvue on a Losmandy GM8 mount was used to take images of eclipsing binary stars. These are easier targets than exoplanets, and the work could proceed in parallel with the upgrades to the 16” Schmidt-Cassegrain telescope in the dome. Once the improvements were complete, the team switched to using the 16” telescope to detect previously known exoplanets. On the basis of the quality of the exoplanet transit data and the associated analyses, the Saint Mary’s team applied to a TFOP subgroup and got news of acceptance at the beginning of August.

“The ball is back in our court to prove that we can use the early access to the satellite data to usefully contribute to TFOP Sub Group 1,” Hill added.

Hofelmann took home the prestigious McKenna Award for her research project at the recent Summer Research Program presentation. “Working on this summer research project was an amazing experience, one that I would not have been able to have elsewhere," she said. "I am grateful for the continued support of the St. Mary’s community on this project.” 

The Saint Mary's College Geissberger Observatory is the vision of the late Professor Ronald P. Olowin and was created with a generous gift from the Geissberger family in memory of Norma Geissberger. Completed in 2004, the observatory stands 277 meters above sea level and allows students to conduct advanced scientific research.

For more information on the TESS Follow-Up Observation Program, visit