() — The search for planets that could support life may have narrowed dramatically.
Scientists have waited and theorized for a long time that the most common type of star in our universe, called an M dwarf, could host nearby planets with atmospheres potentially rich in carbon and perfect for the creation of life. But in a new study of a world orbiting an M dwarf 66 light-years from Earth, researchers found no indication that such a planet could maintain an atmosphere.
Red dwarfs tend to be magnetically active, erupting with intense flares that could strip a nearby planet of its atmosphere over time, or render the surface inhospitable. Credit: NASA/ESA/STScI/G. bacon
Without a carbon-rich atmosphere, it is unlikely that a planet could support living things. After all, carbon molecules are considered the building blocks of life. And the results don’t bode well for other types of planets orbiting M dwarfs, said study co-author Michelle Hill, a planetary scientist and doctoral candidate at the University of California, Riverside.
“The radiation pressure from the star is immense, enough to blow away a planet’s atmosphere,” Hill said. in a post on the website of the University.
M dwarf stars are known for their volatility, as they emit solar flares and rain down radiation on nearby celestial bodies.
However, hope has been held for years that fairly large planets orbiting close to M dwarfs might be in a favorable environment, close enough to their small star to stay warm and large enough to cling to their core. atmosphere.
The nearby M dwarf could be too intense to keep the atmosphere intact, according to the new studiopublished in The Astrophysical Journal Letters.
A similar phenomenon occurs in our solar system: Earth’s atmosphere also deteriorates due to outbursts from its nearby star, the Sun. The difference is that Earth has enough volcanic and other gas-emitting activity to replace the loss. atmosphere and make it barely detectable, according to research.
However, the M dwarf planet examined in the study, GJ 1252b“It could have 700 times more carbon than Earth and still have no atmosphere. It would accumulate initially, but then shrink and erode away,” study co-author and UC Riverside astrophysicist Stephen Kane said in a news release. .
Where did it start and how is it going?
GJ 1252b orbits less than a million and a half kilometers from its parent star, called GJ_1252. The planet reaches sweltering daytime temperatures of up to 1,228°C, according to the study.
The planet’s existence was first suggested by NASA’s Transiting Exoplanet Survey Satellite (TESS) mission. Astronomers then ordered the nearly 17-year-old Spitzer Space Telescope to set its sights on the area in January 2020, less than 10 days before Spitzer will be disabled forever.
The investigation into whether GJ 1252b had an atmosphere was led by astronomer Ian Crossfield of the University of Kansas and involved a team of researchers from UC Riverside, NASA’s Jet Propulsion Laboratory, Caltech, the University of Maryland, the Carnegie Institution for Science, the Max Planck Institute for Astronomy, McGill University, the University of New Mexico, and the University of Montreal.
This illustration shows a possible scenario for the hot, rocky exoplanet called 55 Cancrie, which is nearly twice as wide as Earth. Data from NASA’s Spitzer Space Telescope showed that the planet has extreme temperature swings. Credit: NASA/JPL-Caltech/NASA/JPL-Caltech
The researchers analyzed the data produced by Spitzer for signs of emission, or indications that a gas bubble could enclose the planet. The telescope captured the planet as it passed behind its star, allowing researchers to “observe the light from the star as it passes through the planet’s atmosphere,” giving a “spectral signature of the atmosphere,” or lack thereof. Hill said.
Hill added that she wasn’t surprised to find no signs of an atmosphere, but she was disappointed. She looks for moons and planets in “habitable zones,” and her results made the search for worlds around the ubiquitous M dwarf stars a little less interesting.
The researchers hope to get even more clarity on these types of planets with the help of the James Webb Space Telescope, the most powerful to date.
The Webb will soon lay eyes on the TRAPPIST-1 system“which is also an M dwarf star with a bunch of rocky planets around it,” Hill noted.
“Hope is high that it will be able to tell us whether those planets have an atmosphere around them or not,” he added. “My guess is that M dwarf enthusiasts are probably holding their breath right now to see if we can tell if there is an atmosphere around those planets.”
However, there are still plenty of interesting places to look for habitable worlds. Aside from looking for planets further away from M dwarfs that might be more likely to retain an atmosphere, there are still about 1,000 sun-like stars relatively close to Earth that could have their own planets circling within habitable zones, according to the post. UC Riverside about the study.
