NASA's favorite (and very strange) exoplanets 1:18

(CNN) — Astronomers have found a planet the size of Earth that looks nothing like it.

Instead, the exoplanet, called LP 791-18 d, is thought to be covered in volcanoes and may experience eruptions with the same frequency as Jupiter's moon Io, the most volcanically active place in our solar system, according to researchers.

Data from NASA's Transiting Exoplanet Survey Satellite, the retired Spitzer Space Telescope and ground-based telescopes were used to find the exoplanet. The journal Nature published a study on Wednesday detailing the findings.

LP 791-18 d is located about 90 light-years from Earth, in the constellation Crater, and orbits a small red dwarf star.

Artist's impression of planet LP 791-18 d, which could have volcanic activity. This planet, similar in size to Earth, was discovered by NASA's Spitzer Space Telescope. (Credit: Chris Smith (KRBwyle)/NASA's Goddard Space Flight Center)

Two other known planets also orbit the star: LP 791-18 b, which is estimated to be 20% larger than Earth, and LP 971-18 c, about 2.5 times larger and more than seven times its mass. Astronomers believe that the massive planet LP 971-18 c could contribute to the possible volcanism of the newly detected exoplanet.

As the two objects orbit their star, LP 971-18 c and the new exoplanet LP 791-18 d move closer to each other, allowing the gravitational pull of the larger planet LP 971-18 c to pull on planet d and modify its orbit. At each turn around the star, the trajectory of planet d shifts and takes on a slightly more oval shape. Elliptical revolutions cause the planet's interior to heat up and thereby drive volcanic activity.

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This phenomenon is similar to what happens on Io, which is caught in a gravitational crossfire between Jupiter and its major moons.

But there is still no direct evidence to prove the existence of volcanoes in LP 971-18 d.

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"We don't know if there are volcanoes here," study co-author Ian Crossfield, an associate professor of physics and astronomy at the University of Kansas at Lawrence, said in a statement. "All we know is that this is a small planet that undergoes direct periodic stretching due to its orbit around its star and close to the other planets. That could cause many volcanoes like on Jupiter's moon Io, which is the most volcanically active thing in our solar system. We know that because we've sent things nearby and taken pictures. There is still no such clear evidence with LP 791-18 d."

Future observations of the planet could provide more data as astronomers continue the search for potentially habitable Earth-sized planets.

Volcanic activity and planetary atmospheres

Astronomers calculate that LP 791-18 d lies at the inner edge of the habitable zone; that is, at the distance of a star in which a planet is hot enough to harbor liquid water on its surface.

"LP 791-18 d is tidally locked, which means that the same side is constantly oriented towards its star," Björn Benneke, co-author of the study and professor of astronomy at the Trottier Institute for Exoplanet Research at the University of Montreal, said in a statement. "The day side would probably be too hot for liquid water to exist on the surface. But the amount of volcanic activity we suspect is occurring across the planet could sustain an atmosphere, which could allow water condensation on the night side."

Although volcanic activity sounds like an impediment to the possibility of water and life, it could actually help the planet maintain an atmosphere. Volcanoes can drive interactions between the interior and exterior of a planet.

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"A big question in astrobiology, the field that extensively studies the origins of life on Earth and beyond, is whether tectonic or volcanic activity is necessary for life," said study co-author Jessie Christiansen, a research scientist at NASA's Exoplanet Science Institute at the California Institute of Technology in Pasadena. in a statement. "In addition to possibly providing an atmosphere, these processes could stir up materials that would otherwise sink and become trapped in the crust, including those we think are important for life, such as carbon."

Astronomers are intrigued by how volcanic activity can drive changes in planets. Venus, similar enough in size to Earth, may once have been more like our world.

"On Venus, volcanic carbon dioxide remained in the atmosphere, pushing the planet into an uncontrolled greenhouse state," study co-author Stephen Kane, a professor of planetary astrophysics at the University of California Riverside, said in a statement. "Today, the surface temperature of Venus is more than 454.4 degrees Celsius (850 degrees Fahrenheit), as hot as a wood-fired pizza oven, and the odds of life there are slim. But this may not always have been the case. Volcanoes could be an important piece of the puzzle about what actually happened on Venus. Planets like LP 791-18d can yield important insights into how volcanoes shape planetary environments over time, including those of Venus and Earth."

The search for planetary atmospheres

The larger planet LP 971-18 c is already on the list of targets that the James Webb Space Telescope will observe in the future, and now the study team believes that the newly discovered planet d is also a first-order candidate. Astronomers use the Webb telescope to look for clues to atmospheres around exoplanets and peer into them to determine the chemicals that make up these extraterrestrial atmospheres.

The discovery of LP 971-18 d highlights the importance of data collected by space telescopes. This planetary system was one of the last observing targets of the Spitzer Space Telescope before it retired in January 2020.

"It's amazing to read about the continuation of discoveries and publications years after the end of Spitzer's mission," Joseph Hunt, Spitzer project manager at NASA's Jet Propulsion Laboratory in Pasadena, California, said in a statement. "That really demonstrates the success of our world-class engineers and scientists. Together they built not only a spacecraft, but also a dataset that remains an asset to the astrophysics community."

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