When NASA announced in a news conference Wednesday, Feb. 22, that researchers had found seven potentially Earth-like planets orbiting a star 235 trillion miles away, John Gizis, a professor at the University of Delaware, got a big grin on his face. Gizis actually discovered that star in 1999.

“It’s extremely exciting,” Gizis said from his office in UD’s Department of Physics and Astronomy. “It’s a very small and cool dwarf star. Because it’s temperature is so cool, it hadn’t been noticed before we saw it almost 20 years ago, even though it’s quite close to the sun.”

Gizis was the lead author of the paper identifying the star in 1999, as part of a research team on the Two Micron All-Sky Survey (2MASS), funded by NASA and the National Science Foundation. While Gizis and his colleagues were the first to spot the star, they didn’t notice the seven planets orbiting around it back then. It just didn’t seem practical to search hundreds of stars in those days, he said. Robotic telescopes make this possible today.

Although the star has been called “TRAPPIST-1,” its original name is 2MASS J23062928-0502285, Gizis said. While not nearly as catchy, the name indicates exactly where the star is located in the sky so that it won’t be confused with another celestial object.

Gizis said the 2MASS program of nearly two decades ago has paid off, informing new discoveries today.

“NASA and NSF funded the 2MASS program to take pictures of the whole sky, resulting in a catalog of more than 300 million objects. One of the major results of the team I was on is that it found a number of nearby cool, dim stars that couldn’t be found with previous technology. The idea of the TRAPPIST survey was to go back to these stars that 2MASS found. So now a team focusing on this star has discovered seven planets lined up with our solar system. All seven are lined up just right.”

Gizis said the planets were discovered because the star gets dimmer when a planet passes in front of it.

Does he think any of those seven planets could sustain life?

“Some of the planets are the right distance from the star that they might have liquid water and possibly life, but further study is needed to find out if they are truly habitable,” he said.

Gizis now wants to go back to this star he discovered years ago and take a closer look.

“We’re interested in looking for flares in stars like this using the Kepler telescope, which is looking at Trappist-1 right now. We will definitely try to study the star as soon as the Kepler data is available,” Gizis said. “Huge flares might be a problem for the habitability of the planets. This is really exciting, actually.”