Astronomers believe that in the desert world the atmosphere has completely deflated

(ORDO NEWS) — What if you put an Earth-sized planet in close orbit around an M-dwarf? This is more than an academic question, since M dwarfs are the most numerous stars known to us.

A group of astronomers studying the planet GJ 1252b have found the answer, and it’s not a very good one.

Because this planet is so close to its star, it receives a lot of heat. And this closeness is deadly on the other hand.

“The pressure from a star’s radiation is enormous, enough to blow away a planet’s atmosphere,” says Michelle Hill, an astrophysicist at the University of California, Riverside and co-author of the study. a recent article focuses on GJ 1252b.

The planet is located about 65 light years from Earth and makes two revolutions around its star every 24 Earth hours. The heat of the star makes this world inhospitable.

Astronomers believe that in the desert world the atmosphere has completely deflated
An illustration of the atmosphere being blown off the planet by a nearby star

This is not much different from Mercury in our solar system. There is no atmosphere, and the planet heats up and freezes alternately as it orbits the sun. In fact, the Earth is also losing some of its atmosphere due to solar activity.

However, volcanism and other processes emit gases back into our atmosphere. The earth is lucky; planets like Mercury and GJ 1252b are not. And this is of great importance for the search for worlds favorable for life.

What is it about M-dwarf stars?

There are millions and millions of M-dwarf stars in our galaxy alone. . Their size varies from one tenth to two thirds of the mass of the Sun.

They can be active, sending flares and bursts through their systems. Most of them have at least one planet in their habitable zones, with others at varying distances.

This is not the best combination if you want to find life on their planets. The stellar activity that destroys planetary atmospheres obviously also destroys any chance of life on these worlds.

And because there are so many M-dwarfs, their omnipresence could reduce the number of planets in the galaxy that actually support life. This is bad news for planets like GJ 1252b.

“It’s possible that the state of this planet could be a bad sign for planets further away from this type of star,” Hill said.

“This is what we will learn from the James Webb Space Telescope, which will observe planets like this.”

Even though M dwarfs may be atmosphere killers, it’s not all doom and gloom.

For example, many of the 5000 stars in the vicinity of the Earth are M-dwarfs. Even if most of them make their planets uninhabitable, at least 1000 others (not all of them M-dwarfs) will be able to create conditions suitable for life on their worlds.

“If the planet is far enough away from the M dwarf, it could potentially retain an atmosphere. We cannot yet conclude that all the rocky planets around these stars are doomed to the same fate as Mercury,” Hill said.

“I remain optimistic.”

In search of atmosphere on the GJ 1252b

The situation on GJ 1252b is intriguing science. Astronomers used data from the Spitzer Space Telescope to estimate the planet’s infrared radiation as a secondary eclipse blocked its light.

Measurements showed that the star explodes the planet. Daytime surface temperatures hover around 1227 degrees Celsius (2242 degrees Fahrenheit). This is enough to melt gold, silver and copper.

The heat, combined with the supposed low surface pressure, led the researchers to believe that there was no atmosphere.

But let’s assume for a moment that there WAS a carbon dioxide atmosphere. This would trap the heat on the surface and possibly allow the blanket to last for a while.

However, it turns out that GJ 1252b was not so lucky.

“A carbon planet could be 700 times larger than Earth and still not have an atmosphere. At first it will accumulate, but then narrow and collapse,” said Stephen Cain, UCR astrophysicist and co-author of the study.

In the long term, if the results of this study hold true for a significant population of M-class dwarf stars, the search for habitable planets will shift to other candidates around less volatile stars.


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