Astronomers have found a planet outside of our solar system that is the same size as Earth. It is called LP 791-18 d and the scientists believe it may have volcanoes on its surface! They also think that it could be habitable for life. It is believed the planet may experience volcanic eruptions as frequently as the moon Io, which is the most active volcanic body in our solar system.

About planet LP 791-18 d

In the Crater constellation, about 90 light-years away, LP 791-18 d orbits a small red dwarf star. The team responsible for the discovery believes it is only slightly bigger and heavier than Earth. Due to tidal locking, one side of the planet constantly faces the star, rendering the other side too hot for liquid water. However, the team speculates that volcanic activity across the planet could potentially sustain an atmosphere, allowing water to condense on the dark side.

Karen Collins, astronomer at the Center for Astrophysics, said,

“Only a small proportion of the exoplanets discovered so far are thought to be able to support life. Our discovery of LP 791-18 d gives us more hope that we might one day find signs of life on another planet.”

The team’s initial estimate of the planet’s mass was based on precise measurements of the time it takes for the planet to complete each orbit around its host star. These measurements accounted for the gravitational pull of other planets in the system.

Astronomers suspect that the volcanic activity on the planet may be caused by other planets in its system. Prior to the discovery of LP 791-18 d, two other planets, including LP 791-18 c, were already known to exist in the same system. LP 791-18 c is significantly larger and more massive than planet d.

As planets d and c orbit, they come very near to each other. During these close passes, the larger planet c exerts a gravitational pull on the newly found planet d, causing its orbit to become somewhat elliptical. As planet d travels along this elliptical path, it becomes slightly deformed each time it goes around the star. These deformations can lead to enough internal friction to generate significant heat within the planet, resulting in volcanic activity on its surface. Similarly, Jupiter and some of its moons have a similar impact on Io.

Planet D is located at the innermost boundary of the habitable zone, which is the range of distances from a star that scientists believe could support liquid water on a planet’s surface. According to the research team, if the planet is geologically active, it could sustain an atmosphere. Additionally, temperatures may decrease enough on the planet’s night side to cause water to condense on the surface.

Jessie Christiansen, a research scientist at NASA’s Exoplanet Science Institute at the California Institute of Technology (Caltech), explained,

“A big question in astrobiology, the field that broadly studies the origins of life on Earth and beyond, is if tectonic or volcanic activity is necessary for life. In addition to potentially providing an atmosphere, these processes could churn up materials that would otherwise sink down and get trapped in the crust, including those we think are important for life, like carbon.”

Collins added,

“This discovery is just a first step. With the potential to continue studying this planet with the James Webb Space Telescope, we will be able to fine-tune our observations and learn more about the planet’s likely volcanically fueled atmosphere. Future discoveries will help us understand how the ingredients of life might have come to be on worlds other than our own.”