Exoplanets: The search for habitable planets may have just narrowed


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The hunt for planets that can harbor life may have just been drastically reduced.

Scientists had long hoped and theorized that the most common type of star in our universe — called an M dwarf — could harbor nearby planets with atmospheres potentially rich in carbon and perfect for creating life. But in a new study of a world that orbits an M dwarf 66 light-years from Earth, researchers found no indication that such a planet could hold an atmosphere at all.

Without a carbon-rich atmosphere, it is unlikely that a planet would be hospitable to living things. After all, carbon molecules are considered the building blocks of life. And the findings don’t bode well for other types of planets orbiting M dwarfs, said study co-author Michelle Hill, a planetary scientist and a doctoral student at the University of California, Riverside.

“The pressure from the star’s radiation is immense, enough to blow away a planet’s atmosphere,” Hill said in a post on the university’s website.

M-dwarf stars are known to be ephemeral, to sputter solar flares and to rain radiation on nearby celestial bodies.

But for years the hope had been that fairly large planets orbiting M dwarfs could be in a Goldilocks environment, close enough to their small star to keep warm and large enough to cling to its atmosphere. cleats.

However, the nearby M dwarf could be too intense to keep the atmosphere intact, according to the new study, which was published in The Astrophysical Journal Letters.

A similar phenomenon is occurring in our solar system: Earth’s atmosphere is also deteriorating due to eruptions from the nearby star, the sun. The difference is that Earth has enough volcanic activity and other gassing activity to replace the atmospheric loss and make it barely detectable, according to the study.

However, the M dwarf planet examined in the study, GJ 1252b, “could have 700 times more carbon than Earth, and still might not have an atmosphere. It would build up initially, but then dwindle and erode,” study co-author and UC Riverside astrophysicist Stephen Kane said in a press release.

GJ 1252b orbits less than a million miles from its home star, called GJ_1252. The planet is reaching blistering daytime temperatures of up to 2,242 degrees Fahrenheit (1,228 degrees Celsius), the study found.

The planet’s existence was first suggested by NASA’s Transiting Exoplanet Survey Satellite, or TESS, mission. Next, astronomers ordered the nearly 17-year-old Spitzer Space Telescope to aim its sights at the area in January 2020 — less than 10 days before Spitzer was deactivated forever.

The investigation into whether GJ 1252b had an atmosphere was led by astronomer Ian Crossfield of the University of Kansas and involved a collection of researchers from UC Riverside, NASA’s Jet Propulsion Laboratory, Caltech, the University of Maryland, Carnegie Institution for Science, the Max Planck Institute of Astronomy, McGill University, University of New Mexico and University of Montreal.

They dug into the data produced by Spitzer, looking for emission features or signs that a gas bubble could be enveloping the planet. The telescope captured the planet as it passed behind its home star, allowing researchers to “watch the starlight 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 shocked to find no signs of an atmosphere, but she was disappointed. She’s looking for moons and planets in “habitable zones,” and the results made watching worlds around the ubiquitous M dwarf stars a little less interesting.

Using the James Webb Space Telescope, the most powerful space telescope to date, researchers hope to gain even more clarity about these types of planets.

Webb will soon have his sights set on the TRAPPIST-1 system, “which is also an M dwarf star with a bunch of rocky planets around it,” Hill noted.

“There’s a lot of hope that it will be able to tell us whether those planets have atmospheres around them or not,” she added. “I think the M dwarf enthusiasts are probably holding their breath right now to see if we can tell if there’s an atmosphere around those planets.”

However, there are still plenty of interesting places to hunt on habitable worlds. Aside from looking at planets further away from M dwarfs that are more likely to maintain an atmosphere, there are still about 1,000 Sun-like stars relatively close to Earth that could have their own planets orbiting within habitable zones. , according to the UC Riverside post on the study.

The Valley Voice
The Valley Voicehttp://thevalleyvoice.org
Christopher Brito is a social media producer and trending writer for The Valley Voice, with a focus on sports and stories related to race and culture.


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