Scientists find potentially habitable Earth-like planet not too far from our own solar neighborhood

A team of astronomers from the University of California, Irvine, has discovered a new Earth-like exoplanet that drifts around a red dwarf star in its habitable zone. The star is also just about 25 light-years away from our solar system. 

“This one’s exciting,” said lead author of the study Paul Robertson, UC Irvine assistant professor of astronomy, in a statement. “It’s one of our closest cosmic neighbors. 25 light-years sounds like a long way, but the Milky Way is about 100,000 light-years across, so in that respect it’s our next-door neighbor.” 

The planet, dubbed GJ 3378b, circles a red dwarf star, which is the most common type of star in the Milky Way. For the uninitiated, the habitable zone of a star is the region around it where temperatures are just right for water to exist in its liquid form.

The planet, dubbed GJ 3378b, is roughly twice the size of Earth and was discovered using the Habitable-zone Planet Finder on the 10-meter Hobby-Eberly Telescope at McDonald Observatory in Texas, and the NEID Spectrometer on the WIYN Telescope at Kitt Peak National Observatory in Arizona

The Habitable-zone Planet Finder’s design has been upgraded to track infrared light. When stars become cooler and smaller, they mostly emit energy at infrared wavelengths. “So, we put an infrared spectrometer on a 10-meter telescope, and that gives us more raw light-collecting power to observe these faint stars,” said Robertson in a statement. “This super-Earth gets about 90 percent of the radiation from its host star as Earth gets from its sun, so it’s right in the sweet spot,” said Robertson. But one mystery still lingers. Does this planet have an atmosphere? The planet, the researchers say, sits on the cosmic shoreline—a region around a star where, if a planet sits outside it, the star’s radiation can strip its atmosphere away. This is exactly what happened to Mars, which might have possessed an atmosphere like Earth's once upon a time.

“If you scale the Earth down to the size of an apple, its atmosphere would be about as thick as the skin of the apple,” said Robertson. “That’s just enough to maintain the kinds of surface pressures where you can have liquid water.” While GJ 3378b stands as a promising habitable world candidate, astronomers won't be able to tell for sure if it actually does have an atmosphere until later. NASA's Habitable Worlds Observatory won't launch until the 2040s. But once it does, it will be able to tell whether planets like GJ 3378b have atmospheres or not.

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