Scientists Confirm Existence of Relatively Nearby 'Super-Earth'

Next to Orion's foot, nestled in a river-shaped constellation, is a star circled by a “super-Earth.” And it's one that scientists say might sustain life. 

The planet has a name that looks like a license plate! It's called HD 20794d. It's only 20 light years (118 trillion miles) away from us. It's “among the closest (Earth-like planets) we know about,” said Michael Cretignier in a statement. Cretignier is a postdoctoral Oxford University Physics Department research assistant.

Researchers recently confirmed the planet exists. It was first spotted by Cretignier in 2022. Their findings were published in the journal Astronomy & Astrophysics.

The planet has a mass six times greater than Earth. It revolves around the star 82 Eridani. This star rests in the constellation Eridanus. And the planet lies within that bright star’s “Goldilocks” zone. It's a region that's not too hot and not too cold for life. But HD 20794d has a unique 647-day elliptical orbit. This could create a very harsh, if not unbearable, hot and cold climate.  

The planet's orbit sends it as far away as Mars is from our sun. It also brings it as close as Venus. But it's likely the planet has a thicker atmosphere than Earth’s because of its size. That could help stabilize its climate.

Researchers also said that the big planet isn't large enough to be a gas giant like Jupiter and Saturn. It likely has a rocky surface where water could flow from rivers into lakes and oceans. Cretignier first spotted HD 20794d using a method that detects planets through small wobbles in their stars, resulting from the pull of gravity from orbiting planets. 

Its closeness to Earth means there's hope that future space missions may capture an image of the planet, Cretignier said.  

Reflect: How might discovering a planet that could support life change our understanding of the universe?

Photo of artist's impression of HD 20794d from NASA.