The majority of common star types may not support life on their planets.
The most prevalent form of star in the cosmos, the M dwarf, has an Earth-like planet orbiting it that appears to have no atmosphere at all. The quest for extraterrestrial life may be significantly altered as a result of this discovery. This study implies that a huge number of planets orbiting these stars may likewise lack atmospheres and, as a result, are unlikely to support life because M-dwarfs are so common.
The Astrophysical Journal Letters provides a comprehensive account of the research that produced the discoveries on the GJ 1252b no-atmosphere planet.
In a day on Earth, this planet makes two rounds around its star. In addition to being unfriendly, GJ 1252b is far larger than Earth and is located much closer to its star than Earth is to the sun.
The atmosphere of a planet could be completely destroyed by the star’s radiation, according to Michelle Hill, a UC Riverside scientist and research co-author.
The sun also causes Earth to lose some of its atmosphere over time, but volcanic eruptions and other carbon-cycling mechanisms help to replenish what is lost, making the loss hardly perceptible. However, a planet cannot continue to restore the quantity lost when it is closer to a star.
This is how Mercury is disposed of in our solar system. It does have an atmosphere, but it is very thin and is composed of atoms that the sun has blasted off its surface. These atoms escape into space due to the planet’s intense heat.
Astronomers observed GJ 1252b during a secondary eclipse and studied the planet’s infrared radiation to establish that it is devoid of an atmosphere. This kind of eclipse happens when a planet passes in front of a star, blocking both the light from the planet and light reflected from the star.
The radiation revealed the planet’s sweltering midday temperatures, which are thought to exceed 2,242 degrees Fahrenheit. This temperature is so high that it would melt gold, silver, and copper on the surface of the planet. The researchers believed there is no atmosphere because of the heat and the alleged low surface pressure.
The scientists came to the conclusion that GJ 1252b would not be able to retain an atmosphere even if it contained a huge amount of carbon dioxide, which traps heat.
“The planet wouldn’t have an atmosphere even if it contained 700 times as much carbon as Earth does. According to Stephen Kane, a UCR astronomer and co-author of the paper, it would initially grow up before tapering down and eroding away.
The possibility that planets nearby M dwarf stars might retain their atmospheres is further diminished by the fact that they frequently experience more flares and activity than the sun.
According to Hill, “it’s possible that the state of this planet could be a terrible sign for planets even further out from this type of star.” We’ll learn more about this from the James Webb Space Telescope, which will study planets like these.
A grant from the Future Investigators in NASA Earth and Space Science and Technology programme helped fund Hill’s work on this project.
At the University of Kansas, Ian Crossfield oversaw the research. Along with researchers from Caltech, University of Maryland, Carnegie Institution for Science, Max Planck Institute for Astronomy, University of New Mexico, University of Montreal, and NASA’s Jet Propulsion Laboratory, it also included experts from UC Riverside.
Around the solar system of Earth, there are 5,000 stars, the majority of which are M dwarfs. Even if planets in their orbits are completely ruled out, there are still about 1,000 stars like the sun that might be habitable.
“A planet may be able to keep its atmosphere if it is sufficiently far from a M dwarf. We still can’t say that Mercury’s fate applies to all rocky planets around these stars, Hill added. “I am still hopeful.”