Astronomers have made a groundbreaking discovery of an Earth-size exoplanet – LP 791-18 d – located beyond our solar system. This distant planet is theorized to be carpeted with volcanoes, and could potentially undergo volcanic outbursts as often as Jupiter’s moon Io, which is the most volcanically active body in our solar system. The research team used data from NASA’s TESS and retired Spitzer Space Telescope, as well as ground-based observatories to make the discovery. The paper was led by Merrin Peterson, a graduate of the Trottier Institute for Research on Exoplanets (iREx) at the University of Montreal, and was published in the May 17 edition of the scientific journal Nature.
LP 791-18 d is a fascinating exoplanet due to its tidally locked nature and potential for volcanic activity. While the day side is likely too hot to sustain liquid water on the surface, the night side may possess an atmosphere that allows water to condense, making it a potentially unique and interesting environment. LP 791-18 d, orbits a small red dwarf star located approximately 90 light-years away in the constellation Crater. This planet is slightly larger and more massive than Earth and is part of a system that already includes two other known planets.
Through this discovery, astronomers have confirmed the presence of three planets circling the star LP 791-18.The innermost planet, b, is about 20% larger than Earth in size, while the outermost planet, c, is more than seven times its mass and close to 2.5 times its size.Through gravitational tugs from the more massive planet C, planet D is pulled into an elliptical orbit that causes internal friction and heating.This heating can produce enough energy to cause volcanism at the surface of planet D, similar to the relationship between Jupiter and Io.
The research team’s hypothesis has suggested that Planet D is located in the perfect position to potentially maintain liquid water on its surface. If the planet is as geologically active as the team suspects, this would help to maintain an atmosphere which could cause temperatures to drop enough on the night side for water to condense on the surface.
Planet c has been approved for observing time on the James Webb Space Telescope and now planet d is being considered as an excellent candidate for further studies.The research team plans to use the mission to explore the potential for the presence of life on each of these planets. Astrobiology, which examines the origin of life on Earth and beyond, will be used to help assess conditions that could be favorable for life. Factors such as tectonic and volcanic activity can have an effect on the presence of atmosphere and churn up materials that could be important for life. The James Webb Telescope’s observations may provide an answer as to whether life can exist on either planet.
Spitzer’s observations of the system were among the last that the satellite collected before it was decommissioned in January 2020, ending a mission that had begun in 2003. The success of this mission was made possible thanks to the hard work of those who designed and built the spacecraft – engineers and scientists alike – as well as those who produced the data set that continues to be an asset for the astrophysics community. Joseph Hunt, Spitzer project manager at NASA’s Jet Propulsion Laboratory in Southern California, highlights the importance of this success for the scientific community, emphasizing that Spitzer’s discovery and publications continue to be of relevance years after its end of mission.