This cartoon shows the transiting planet GJ 1132b to scale against its host star GJ 1132. Credit: Zach Berta-Thompson
Scientists have discovered a new exoplanet that, in the language of “Star Wars,” would be the polar opposite of frigid Hoth, and even more inhospitable than the deserts of Tatooine. But instead of residing in a galaxy far, far away, this new world is, galactically speaking, practically next door.
The new planet, named GJ 1132b, is Earth-sized and rocky, orbiting a small star located a mere 39 light-years from Earth, making it the closest Earth-sized exoplanet yet discovered. Astrophysicists from MIT and elsewhere have published these findings today in the journal Nature.
Based on their measurements, the scientists have determined that the planet is a roasting 500 degrees Fahrenheit, and is likely tidally locked, meaning that it has a permanent day and night side, presenting the same face to its star, much like our moon is locked to the Earth.
Because of its scorching temperatures, GJ 1132b most likely cannot retain liquid water on its surface, making it uninhabitable for life as we know it. However, scientists say it is cool enough to host a substantial atmosphere.
The planet is also close enough to Earth that scientists may soon be able to find out much more about its characteristics, from the composition of its atmosphere to the pattern of its winds—and even the color of its sunsets.
“If we find this pretty hot planet has managed to hang onto its atmosphere over the billions of years it’s been around, that bodes well for the long-term goal of studying cooler planets that could have life,” says Zachory Berta-Thompson, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research. “We finally have a target to point our telescopes at, and [can] dig much deeper into the workings of a rocky exoplanet, and what makes it tick.”
A nearby solar neighbor
Berta-Thompson and his colleagues discovered the planet using the MEarth-South Observatory, a Harvard University-led array of eight 40-centimeter-wide robotic telescopes located in the mountains of Chile. The array monitors small, nearby stars called M dwarfs, which are scattered all over the night sky. Scientists have determined that these kinds of stars are frequently orbited by planets, but haven’t yet found Earth-sized exoplanets that are close enough to study in depth.