A planet, almost the same size of the Earth, which co-exists in our galaxy and orbits a dim star, is presenting compelling evidence of volcanic activity beyond our solar system.
Scientists have inferred that this rocky world is likely covered in volcanoes, resembling Jupiter’s moon Io, known for its high volcanic activity. Although direct observation of the planet’s volcanism is not yet possible, researchers believe that the gravitational interaction with a larger neighbouring planet causes the newly discovered planet to experience heating and surface volcanic activity, akin to Io.
The newly identified planet is an exoplanet, a planet outside our solar system. University of Kansas astronomy professor Ian Crossfield, one of the authors of the study published in the journal Nature, explained, “There is not yet any direct observational evidence of exoplanet volcanism, but this planet is a particularly likely candidate.”
This unique planet does not rotate, with one side perpetually facing daylight and the other in darkness. “On the dayside, it is too hot for liquid water, so it is likely very dry and hot – likely a desert. On the night side, there is possibly a large icy glacier,” said study co-author Björn Benneke, head of the astronomy group at the University of Montreal.
However, the most intriguing region is near the terminator, where the day and nightside meet. Here, the melting of water from the nightside glacier could potentially form liquid surface water. Volcanism is expected to occur throughout the planet, even under the ice on the nightside and possibly under the water near the terminator, added Benneke.
Situated approximately 86 light-years away from our solar system in the Crater constellation of the Milky Way, this planet is slightly larger than Earth and orbits a red dwarf star. The star is significantly smaller and cooler than our sun, and the planet completes its elliptical orbit around it in just 2.8 days. The surface temperature of the planet appears to be slightly warmer than Earth, and it resides within the habitable zone, also known as the Goldilocks zone, where conditions may be suitable for liquid water and potentially life.
University of California, Riverside planetary astrophysicist Stephen Kane said “I imagine a rugged, young surface for the planet after many millions of years of constant volcanic activity. Since the gravitational effects don’t care about day and night side, I also suspect the volcanic activity to be evenly spread over the planetary surface.”
Kane added that the planet is still releasing gases from its interior, indicating the presence of an atmosphere. However, due to its inhospitable environment, the planet is unlikely to be habitable, though the possibility of life adapting to such conditions cannot be ruled out.
The planet’s orbit is positioned between two other planets in the system. The innermost planet is around 20% larger than Earth, while the outermost planet is approximately 250% larger.
The discovery of this planet was made using NASA’s Transiting Exoplanet Survey Satellite (TESS), the now-retired Spitzer Space Telescope, and ground-based observatories.
However, there is still much to learn about volcanism and the duration of outgassing processes on planets. Kane highlights that Venus, Earth’s twin planet, was only recently confirmed to be volcanically active, emphasizing the ongoing exploration and discovery of our celestial neighbours.