SPACE — Scientists have discovered a potentially habitable planet undergoing atmospheric erosion, a process that could ultimately make the world, Trappist-1e, inhospitable to life. The atmospheric stripping appears to be caused by electrical currents created as the planet moves around its parent red dwarf star.
This is a significant discovery because the Trappist-1 system, located just 40 light years from Earth, has been one of the main targets for the hunt for extraterrestrial life. Of the seven Earth-like rocky worlds in the system, at least 3 of them are located in the habitable zone, which is the region around a star that is suitable for the existence of liquid water.
However, a planet without an atmosphere will not be able to accommodate liquid water, even if it is in the habitable zone, also known as the Goldilocks zone. This suggests that, although Trappist-1e is in the habitable zone of the star Trappist-1, its habitability may be fleeting.
Phenomena that affect Trappist-1e’s atmosphere could also impact the atmospheres of other planets in the habitable zone. That’s bad news for the possibility of finding life in the system.
Also Read: TRAPPIST-1, Another Solar System with 7 Twin Planets of Earth
How the Atmosphere Separates from the Planet
Trappist-1e is roughly the size of Earth, but has a mass about 0.7 times that of our planet. It is the fourth planet from its star, orbiting just 0.028 times the distance between Earth and the sun, completing one orbit in just 6.1 Earth days.
However, because the star Trappist-1 is much smaller and cooler than the Sun, its habitable zone is much closer to its surface compared to our star’s habitable zone. Therefore, it is not radiation from the red dwarf that erodes Trappist-1e’s atmosphere, but rather the wind of charged particles exhaled from the star.
Member of the research team and astrophysicist at Harvard & Smithsonian,
Cecilia Garraffo said her team was observing how the planet’s space weather changed through its orbit. Trappist-1e’s very rapid transition between very different stellar wind conditions and pressures leads to a kind of compression and relaxation of the planet’s magnetic field.
“It drives strong electric currents in the upper layers of the atmosphere, the ionosphere, which heats the atmosphere like an electric heater,” Garraffo told Space.com.
Garraffo explained that the Earth also experiences variations in the solar wind which causes similar heating in our atmosphere. The difference is that the heating experienced by Trappist-1e is 100,000 times stronger than that experienced by Earth due to the solar wind.
Also read: Webb Telescope Reveals the Mystery of the Most Earth-Like Planet, TRAPPIST-1b
This happens because Trappist-1e is moving rapidly around its star, and that motion drives strong ionospheric currents that then dissipate and create extreme heating. The research team calls this voltage-driven Joule heating.
Although the team had predicted this effect in 2017, they were surprised by how devastating the impact they found today. “The power of Trappist-1e can be so strong that its heat vaporizes the upper atmosphere. “Over millions of years, the planet could lose its entire atmosphere due to this phenomenon,” said Garraffo.
2024-02-29 08:32:00
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