Mason researcher helps lead the search for new exoplanets

Peter Plavchan is looking for new planets

Peter Plavchan is an associate professor in the Department of Physics and Astronomy and the director of the Mason Observatory.

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A George Mason University professor is part of team of scientists running a global network of telescopes dedicated to the confirmation and validation of exoplanets in our galaxy. 

Peter Plavchan, an associate professor in the Department of Physics and Astronomy within the College of Science and the director of the Mason Observatory, is the co-principal investigator for two Miniature Extreme Radial Velocity Array (MINERVA) observation facilities, including the first in the United States. Plavchan, who drew national and international headlines earlier this year when he and his team of students discovered a new exoplanet the size of Neptune, recently received a grant of $126,758 from the National Science Foundation for his team’s research. 

The U.S facility (MINERVA North) atop Mt. Hopkins in Arizona combines five robotic telescopes that simultaneously fiber-feed two small, bench-mounted spectrometers. The Australian facility (MINERVA Australis) combines five robotic telescopes as well that fiber-feed a single spectrometer atop Mt. Kent in Toowoomba, Australia. 

“MINERVA has been used to help confirm or validate about a dozen planets orbiting nearby stars.” Plavchan said. 

The MINERVA observatories, whose data helped in the confirmation of AU Mic b, follow up on possible planetary candidates, including those identified by the NASA TESS mission, by using the Doppler Effect to measure the color of light originating from a star. Using the highly advanced spectrometers, Plavchan and his team look for even the smallest deviations in color from a star that may have resulted from changes to the star’s velocity. 

“Physics tells us that a change in velocity or speed means there is an acceleration,” Plavchan said. “That acceleration, according to Newton’s Second Law of Physics, says that a force is acting on that star. And that force is the gravitational tug of something going around it. It’s kind of a chain of logical reasoning—with the color changes of stars, we can infer the presence of planets orbiting around that star.” 

Australia’s University of Southern Queensland is the lead institution in the MINERVA Australis project. There are fewer telescopes in the Southern Hemisphere, and we can observe stars that telescopes in the Northern Hemisphere can’t see because the Earth is in the way, Plavchan said.  

Harvard University’s Jason Eastman, who serves as the other co-PI for MINERVA North, credits both facilities for the knowledge they will bring about other planets and the universe’s origins. 

“With MINERVA,” he said, “we should be able to double the number of planets with such measurements, and shed light on the migration mechanism for large, close-in planets.”

Plavchan said the first two years of the MINERVA project have been very productive. The team looks forward to uncovering more of the galaxy’s secrets.

“We’ve answered a question humanity has wondered for millennia—are there other worlds out there? The answer is a definitive yes, and there are billions more worlds with unexplored lands waiting to be found,” he said.