This Earth-Sized Planet Turns Out to Be Our Nearly Next-Door Neighbor

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An illustration showing a planet orbiting a small red dwarf star. Dotted Yeti/Shutterstock

It's not every day that astronomers discover a rocky planet hanging out in our own galactic neighborhood. Especially one that's just a little bigger than our own beloved rock.

Which is why newly named GJ 1252 b is so special.

The planet was spotted by an international team of scientists while they were sifting through data from NASA's Transiting Exoplanet Survey Satellite (TESS). Their findings were published this month in the academic journal arXiv, but have yet to be peer-reviewed.

"Based on the TESS data and additional follow-up data we are able to reject all false positive scenarios, showing it is a real planet," the researchers note in the paper.

Unlike most newfound planets, GJ 1252 b isn't an ice and gas giant. Rather, it's rocky, just a little bigger than Earth — and practically next door to us. Well, 66.5 light-years next door. On the cosmic scale, that's really just a hop, skip and a warp jump away.

But even if we could figure out how to set sail for this planet, we probably wouldn't want to spend any time there. GJ 1252 b isn't the kind of place to raise the kids. In fact, researchers say it isn't a likely candidate for supporting any kind of life. That's because it zips around its sun — a red dwarf star — every 12.4 hours. Although, its star is much smaller than our sun, the rapid orbit suggests the planet's surface is baking hot. What's more, the planet is likely tidally locked, keeping the hot side hot and the cold side, really cold.

But for scientists, that doesn't make GJ 1252 b any less a glittering prize.

GJ 1252 b joins a small but rapidly growing cast of rocky planets we're finding in our cosmic environs. The most recent additions — Pi Mensae c and LHS 3844 b — were described in September 2018 and reside 60 and 49 light-years away, respectively.

Most of the roughly 4,100 planets that have been identified in our galaxy are of the big, gassy and cold variety. That left a small, rocky planet-sized hole in our understanding of the cosmos.

Could Earth really be such a rare marble?

More likely, we see fewer rocky planets because they're harder to detect than their giant, gassy cousins. Not only are they smaller, but as Science Alert notes, they generally orbit stars that are too small to light them up for further investigation.

On the other hand, GJ 1252 b, with its close and frequent orbit, offers scientists frequent chances to monitor it as it passes in front of its sun.

"The host star proximity and brightness and the short orbital period make this star-planet system an attractive target for detailed characterisation," the researchers note.