Exoplanets: The search for habitable planets may have just narrowed down

Exoplanets: The search for habitable planets may have just narrowed down
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Hunt for planets that could harbor life may have narrowed dramatically.

Scientists have long hoped and theorized That the most common type of star in our universe – called an M dwarf – could potentially host nearby planets with atmospheres that are 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 hold onto an atmosphere.

Without a carbon-rich atmosphere, a planet is unlikely to 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 author Michelle Hill, a planetary scientist and PhD candidate at the University of California, Riverside.

“The pressure from the stellar radiation is so great, enough to blow up a planet’s atmosphere,” Hill said. in an article on the university’s website.

M dwarf stars are known to be volatile, emit solar flares and rain radiation on nearby celestial bodies.

But for years there has been hope that very large planets orbiting M dwarfs might be close enough to their small stars in the Goldilocks environment to keep them warm and large enough to cling to their atmospheres.

However, the nearby M dwarf may be too dense to keep the atmosphere intact relative to the atmosphere. new workPublished in The Astrophysical Journal Letters.

A similar phenomenon happens in our solar system: Earth’s atmosphere is also disrupted by explosions from its nearby star, the sun. The difference is that Earth has enough volcanic activity and other gas-emitting activity to replace atmospheric loss and make it barely detectable, according to the study.

However, the M dwarf planet studied in the study, GJ 1252b“It could have 700 times more carbon than Earth has and still wouldn’t have an atmosphere. It would build up initially, but then tapered and eroded,” Stephen Kane, co-author of the study and UC Riverside astrophysicist, said in a news release.

GJ 1252b orbits less than a million miles from its parent star, GJ_1252. The study found that the planet reaches sweltering daytime temperatures of as much as 2,242 degrees Fahrenheit (1,228 degrees Celsius).

The existence of the planet was first suggested by NASA’s Transit Exoplanet Survey Satellite, or TESS mission. Then, astronomers ordered the nearly 17-year-old Spitzer Space Telescope to adjust its gaze over the region less than 10 days ago in January 2020. Spitzer disabled forever.

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

This drawing shows a possible scenario for a hot, rocky exoplanet called 55 Cancrie, which is almost twice as wide as Earth.  Data from NASA's Spitzer Space Telescope showed that the planet had extreme temperature fluctuations.

They scrutinized the data produced by Spitzer, looking for signatures of emissions, or signs that a gaseous bubble might cover the planet. Hill said the telescope captured the planet as it passed behind its own star, giving researchers “a spectral signature of the atmosphere,” or lack thereof, “to look at the starlight as it passes through the planet’s atmosphere.”

Hill added that he wasn’t shocked but disappointed when he found no signs of atmosphere. Searching for moons and planets in “habitable zones” and looking at worlds orbiting ubiquitous M dwarf stars made the results a little less interesting.

Researchers hope to gain greater clarity about such planets with the help of the James Webb Space Telescope, the most powerful space telescope to date.

Webb will soon catch your eye TRAPPIST-1 system“This is also an M dwarf star with a lot of rocky planets around it,” Hill said.

“There’s a lot of hope that it can tell us whether these planets have an atmosphere around them,” he added. “I think M dwarf enthusiasts are probably holding their breath right now to see if there is an atmosphere around these planets.”

However, there are many interesting places to hunt for habitable worlds. In addition to looking for planets farther away from M dwarfs that may be more likely to retain an atmosphere, there are about 1,000 sun-like stars that are relatively close to Earth that could cause their own planets to rotate within the habitable zones, according to UC Riverside’s post on the study. .

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