Ross 128 b: Potentially Habitable Alien Planet is Hurtling Toward Us

A new exoplanet that could theoretically host a climate hospitable to life has been discovered just 11 light-years away from Earth—and it's speeding closer every day. Scientists announced the discovery in a paper due to be published in the journal Astronomy & Astrophysics.

The new planet has been named Ross 128 b after its star, which is a small, quiet red dwarf just down the street from us in our Milky Way galaxy. Ross 128 b circles it every 10 days or so, since it is about 20 times closer to its star than the Earth is to our sun. The new planet is also about a third again as large as Earth.

The astronomers who spotted it think its temperature should be between -76 and 68 degrees Fahrenheit, which is pretty pleasant as exoplanets go. That said, they're not sure how long liquid water could last on Ross 128 b's surface, which would shape just how habitable they would consider it.

11_15_ross128b_exoplanet An artist's idea of what Ross 128 b and its star may look like. ESO/M. Kornmesser

Still, it's a pretty appealing target as exoplanets go. That's because the only planet we know of so far that's closer to us, Proxima b, may have a little problem with its star throwing giant tantrums of ultraviolet and X-ray radiation. That sort of barrage could be deadly to any life—native or exploratory—on the planet's surface. Ross 128 b doesn't have the same type of explosive temperament; it's much tamer.

To find Ross 128 b, the team had to sift through more than 10 years' worth of data from a Chile-based instrument called the High Accuracy Radial Velocity Planet Searcher, plus similar data from two other long-term studies.

Related: Proxima Centauri: Our closest cosmic neighbor may have an entire solar system we never knew about

Now that they've spotted it, researchers plan to keep monitoring Ross 128 b to get a better sense of what's happening on its surface. In particular, they'd like to have a better sense of what its atmosphere is made of, since that could make it more or less conducive to hosting life. Unlike most exoplanets, Ross 128 b is actually close enough that an instrument called the Extremely Large Telescope may be able to spot oxygen in its atmosphere, which would instantly make it the most interesting exoplanet to date.

And while Ross 128 b is currently only the second-closest exoplanet to us, it's due for a promotion since its star is moving toward our sun. It should become our nearest neighbor in only 71,000 years, a blink of an eye in space time.

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