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Investigate the potential for life around the smallest stars in the galaxy

The concept of the James Webb Space Telescope artist, the successor to the Hubble Space Telescope. Credit: NASA

When the world’s most powerful telescope is launched into space this year, scientists will ask whether the Earth-sized planets in our “neighborhood of the sun” have an atmosphere, an important prerequisite for life. Learn


They are planet It orbits the M-type dwarf, the smallest and most common type of star in the galaxy. Scientists now don’t know how common it is for planets like Earth around this type of star to have the properties that make them habitable.

“As a starting point, it’s important to know if the small rocky planets orbiting M-Dwarf have an atmosphere,” said Dalia Pidrodetsuka, a doctoral student at the University of California, Riverside’s School of Earth and Planetary Sciences. Said. “If so, it opens up our quest for life outside our solar system.”

To fill this gap in understanding, Pidrodetsuka and her team studied whether the soon-to-be-launched James Webb Space Telescope or the Hubble Space Telescope currently in orbit could detect the atmosphere of these planets. They also modeled the types of atmosphere that could be discovered, and how they, if present, would be distinguished from each other. Research is currently Astronomical Journal..

Co-authors of the study include UCR astrobiologists Edward Schwieterman and Stephen Kane, as well as scientists at Johns Hopkins University, NASA’s Goddard Space Flight Center, Cornell University, and the University of Chicago.

The central star of the study is an M-type dwarf called L 98-59, which measures only 8% of the Sun’s mass. It’s small, but only 35 light-years from Earth. Its brightness and relative proximity make it an ideal target for observation.

Immediately after they are formed, M-dwarfs go through a stage where they can shine two orders of magnitude brighter than normal. Strong UV light at this stage can dry the orbiting planets, evaporate water from the surface, and destroy many of the gases inside. atmosphere..

“I wanted to know if the ablation was complete in the case of two rocky planets, or if those terrestrial planets were able to replenish their atmosphere,” said Pidrodetsuka.

The researchers modeled four different atmospheric scenarios. One is a scenario where the world of L 98-59 is dominated by water, one is a scenario where the atmosphere is mainly composed of hydrogen and a carbon dioxide atmosphere like Venus, and the other is hydrogen in the atmosphere. The included scenarios. He escaped into space, leaving only oxygen and ozone.

They found that two telescopes could provide supplementary information using transit observations that measure the dip of light that occurs when a planet passes in front of the star. The L 98-59 planet has the Earth much closer to the stars than the Sun. They complete their orbits within a week, making telescopic transit observations faster and more cost-effective than observing other systems far away from them. Performer..

“To detect or eliminate a cloudless hydrogen or vapor-dominated atmosphere, we only need a few passes through Hubble,” says Schwittermann. “In just 20 transits, Webb makes it possible to characterize atmospheric gases that are dominated by heavy carbon dioxide or oxygen.”

Of the four atmospheric scenarios examined by the researchers, Pidhorodetska said that a dry, oxygen-dominated atmosphere is most likely.

“The amount of radiation these planets receive at that distance from the stars is intense,” she said.

There may not be a suitable atmosphere for today’s life, but these planets are important to what happens to Earth under different conditions and what can happen in a world like Earth elsewhere in the galaxy. You can get a glimpse of it.

The L 98-59 system was discovered only in 2019, and Pidhorodetska said he was excited to have more information about the system when Webb was launched later this year.

“We are on the verge of revealing the secrets of the star system that were hidden until very recently,” said Pidrodetsuka.


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For more information:
Daria Pidhorodetska et al, L 98-59: Asteroid Benchmark System for Future Atmospheric characterization, Astronomical Journal (2021). DOI: 10.3847 / 1538-3881 / ac1171

Quote: Https: //phys.org/news/2021-09-potential-life-galaxy-smallest-stars.html, the smallest star in the galaxy obtained on September 29, 2021 (September 29, 2021) Investigate the potential of life around

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Investigate the potential for life around the smallest stars in the galaxy

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