Far out: Dartmouth student finds two new exoplanets

Lots of people picked up new hobbies during the pandemic. But during the lockdown, recent graduate Jack Duranceau began developing a particularly unique way to pass the time: researching young exoplanets and the stars they orbit.

“The nice thing about astronomy is that it’s fully remote – at least it can be. We’re not gonna go to these stars, it would take too long,” said Duranceau, who just graduated from Dartmouth, where he majored in physics and astronomy.

Duranceau’s work — which resulted in the discovery of two new exoplanets, or planets beyond the reaches of our own solar system — drew his attention about as remote as you can get. In fact, the star Duranceau would end up looking at was located 257 light years, or about 1.5 quadrillion miles, away from us.

The research Duranceau started under assistant professor Elizabeth Newton would eventually lead to his senior thesis, which included his exciting discovery of the new exoplanets.

Duranceau found the planets while looking at data from a NASA satellite to first determine if the suspected exoplanets existed at all.

“What's interesting about this system is that it's pretty similar to the sun. And the star has the same mass and radius, you know, plus or minus a tiny percent,” Duranceau said. “It’s pretty interesting to see what our own solar system might have looked like if things had gone differently or at different points in time.”

Duranceau’s research also tried to measure the age of the star that the planets orbited. To determine the age of a star, researchers look at spectra, or the measures of how much light is at different wavelengths. Knowing that different elements absorb light at different wavelengths, researchers can learn more about the star by its light.

“You can look at what wavelength you see dips in your spectra and trace that back to see what elements are in your star, which I just think is really cool. I love spectra,” Duranceau said.

Finding the amount of lithium in a star by its spectra can help in estimating the star’s age. In this case, the two planets Duranceau found and the star they orbit were young, which helps paint a picture of planetary evolution.

“Looking at younger stars is like looking at different snapshots in time because we can't really fit and wait for, you know, a billion years to see how one system changes over time,” he said. “So we have to look at tons of them from all sorts of different timeframes.”

Post graduation, Duranceau plans to wrap up his research at Dartmouth before applying to PhD programs in astrophysics.