Notre Dame to upgrade planet imager that searches for giant planets

Author: Deanna Csomo McCool

Sometime during the summer, a flatbed truck will roll onto the University of Notre Dame campus and deliver a special instrument that could hold one of the keys to understanding the universe.

The Gemini Planet Imager (GPI) was installed in 2013 on a telescope in Chile, the southern of the “twin” Gemini telescopes. GPI is designed to image giant planets outside of our solar system as well as rings of asteroids orbiting nearby, young stars. But although the imaging system is stable and needs little if any maintenance, the equipment inside needs an upgrade, according to Jeffrey Chilcote, assistant professor in the Department of Physics.

After the upgrade, which will take 15 to 18 months, GPI will be shipped to Hawaii, where the northern Gemini telescope is located.

Chilcote Vertical

The upgrade is a collaboration among Cornell University, Stanford University, the University of California-San Diego, Space Telescope Science Institute, and the Herzberg Astronomy and Astrophysics Research Centre. The project has received a $2.6 million grant from the National Science Foundation (NSF).

GPI is three instruments in one, working in tandem. Chilcote likened its process to blocking out the light from a lighthouse in order to see a firefly.

“GPI’s entire job is to very quickly correct the atmosphere; to get rid of the light from a star to reveal the planet,” he said.

It is like a camera body – the part of the camera without the lens – and attaches to the telescope. As part of this program, students and researchers from other universities will visit Notre Dame over the summer and rebuild the equipment. Because Gemini’s instruments are the same size and shape, the revamped GPI will install easily onto the telescope in Hawaii.

While a graduate student at UCLA, Chilcote was part of the team that built the integral field spectrograph for the GPI. Often astronomers find planets by observing their effects upon stars, which appear to “wobble,” and are detected through doppler. But direct imaging uses the optics and a spectrograph to isolate the light from large planets, allowing astrophysicists to analyze the properties of the light to determine the makeup of the planets’ atmospheres.

Design work began on the first iteration of GPI in 2003 with construction beginning in 2008. It was installed in Chile five years later, and has recently completed a five-year survey of nearly 600 stars to determine how common giant extrasolar planets are.

“They’re on the rarer side than we originally thought, but they still fit within planet population models,” Chilcote said.

The upgrade will improve the GPI — which is now using technology that’s a decade old — and allow it to perform several new surveys with cutting-edge equipment for the next decade. It will be able to observe fainter, younger stars and study planets earlier in their formation, detect planets similar in size to Jupiter, and will operate more efficiently to support studies by the entire astronomical community.

The exchange program of graduate students who will be coming to Notre Dame to work on the upgrade will also be enhanced by mentoring and professional development programs.

In addition the $2.6 million from the NSF, the project received another $1 million from the Heising Simons Foundation, through the University of California-San Diego.