Canadian astronomers discover new Earth-like planet potentially covered in volcanoes

CTV National News: Earth-sized exoplanet found Heather Butts reports on the Canadian connection to the recent discovery of an Earth-sized exoplanet which could potentially support life.

Around 90 light years away from our solar system is an exoplanet covered in volcanoes, around the same size as the Earth and potentially able to support life.

And it’s the discovery of Canadian astronomers.

“We were super excited about this,” Björn Benneke, head of the astronomy division within the department of physics at the University of Montreal, told CTV National News.

He said when his team discovered the planet, they all felt a thrill over having a discovery no one else knew about yet.

“My students and I were the only ones in the world that knew about this extra Earth that is out there that is potentially a game changer for how we understand these planets, or understand the solar system, so that was a huge moment.”

Exoplanet is the term for a planet that exists in solar systems outside of our own. Scientists have been increasingly searching for exoplanets that may be able to support life for years, but it’s still rare to find ones that fall within certain parameters.

“What is particularly exciting about these Earth-size planets, about these temperate planets where temperatures are quite similar to the Earth, is those are the ones where we will look for life in the future, so this one here — it’s a potential candidate for this,” Benneke said.

Some of the key factors astronomers look for are planets of a similar size to Earth that orbit their star at a distance not too far away and not too close — within the “habitable zone” of temperature that could allow for liquid water to form on the surface of the planet.

This new planet hits those markers, but also comes with some unique properties that are making scientists excited.

Benneke’s team is dedicated to searching for Earth-like exoplanets and mapping the diversity of their atmospheres and makeups.

They found the new planet using NASA’s “TESS” — Transiting Exoplanet Survey Satellite.

How it works is that as a planet passes in front of its star, it blocks some of the light, causing a slight drop in brightness. TESS is able to spot these dips in light and map out planet transits to confirm the presence of a planet.

The team also used data from the retired Spitzer Space Telescope to discover the planet could possibly support life.

“It has some properties that are very, very similar to Earth. It’s the same size, it’s a similar mass, in terms of temperatures, relatively comparable, at least globally,” Benneke said. “But there are also quite some differences.”

One of those differences is that this planet, which orbits a much smaller star than ours, doesn’t rotate the way Earth does — instead it is locked in its orbit around its star, similar to the way the moon orbits the Earth.

“This means the same side of the planet always faces towards the star,” Benneke said. “It’s a permanent day side.”

The planet is officially designated as LP 791-18d, but it has another name: Reykjavik, after the capital of Iceland.

The nickname comes from the team’s theories about the makeup of the planet.

They believe it could undergo volcanic outbursts as often as Jupiter’s moon Io, the most volcanically active body in our solar system.

“Volcanoes are exciting because they bring things to the surface of the planet that might bring the building blocks of life,” Dan Riskin, CTV’s Science and Technology Specialist, told CTV National News. “So any time there’s a volcano, people get excited.”

How do scientists know that this planet is likely to have significant volcanic activity? Because they’ve been studying this system for a while.

LP 791-18d is not the only planet that orbits this particular dwarf star. Two other planets were previously discovered by TESS in 2019, known as LP 791-18 b and c.

This new planet orbits in between the two, at an intermediate distance from the star, with Planet c — which is about 2.5 times bigger than Earth — orbiting the farthest from the star. When tracking the movements of these planets, however, astronomers realized that Planet c was passing very closely to the new planet, so closely that the larger planet’s gravity is definitely impacting the smaller one.

Every time the larger planet passes close to LP 791-18d, it pulls on the smaller planet, deforming it slightly in a process called tidal heating.

“The significant friction generated by tidal heating in the planet is responsible for heating its interior to a considerable extent, ultimately enabling the existence of a subsurface magma ocean,” Caroline Piaulet, a UdeM Ph.D. student who was involved in the discovery, said in a press release. “In our Solar System, we know that Jupiter’s moon Io is affected by Jupiter and its other moons in a similar way, and that world is the most volcanic we know.”

The permanent night side of the planet is where astronomers believe that water may be able to form. With ice, water and volcanoes, researchers picture it like Iceland — hence the nickname.

While TESS continues to look for signs of planets, new worlds or exoplanets, the team is hoping that they can get a closer look at this new exoplanet in particular through the James Webb telescope, the largest and most advanced telescope ever built.

“Once James Webb turns its attention to it, we’re going to have a much better view,” Riskin said. “Right now, it’s a lot of theoretical stuff about what might be there and we’re going to have a close look soon with that new telescope and it’s going to make it all worthwhile.”

Because the planet’s star is so small — only a little bit bigger than Jupiter — researchers believe that the James Webb telescope should be able to actually see the planet’s atmosphere.

Scientists have already secured observing time with the James Webb telescope for the larger planet, Planet c, which will shed more light on the system.

“Everyone thinks of NASA when they think of space science, but here you have Canadian researchers, a Canadian university,” Riskin said. “And ultimately, it’s that James Webb telescope, which is partly Canadian, that’s going to have a closer look. So Canada has a lot to be proud about.”