Our excitement and happiness for finding 39 light years distant Trappist-1 system may melt down after being conducted several studies. Although NASA has high hopes for 7 Earth-sized planets, even the public involved in their naming, it seems like planets aren’t habitable after all. At least not in the sense most people use the word. No, we didn’t lose all chances, just they’re significantly lower.
Questionable atmospheres of the planets
Trappist-1 is a dwarf star, which is about one-twelfth the size of our sun and much cooler. All 7 planets orbiting close to the star, which keeps them from freezing over. Being tidally locked means one hemisphere constantly faces their sun while the other side is in perpetual darkness. Put in other words, day, night, morning and evening aren’t times of the day, but places. In such conditions, planets get blasted with high-energy radiation.
Astronomers from the University of Geneva Observatory in Switzerland have compared the two types of radiation being emitted from the Trappist-1. They came to the conclusion that the star isn’t that old. More importantly, they weren’t sure how much of the atmosphere has left on the planets. Namely, radiation from the star ionizes gasses in the planet’s atmosphere, allowing the particles to be pushed up and away from the planet’s surface on streams of solar wind. The lack of atmosphere makes unlikely that liquid water could flow on planet’s surfaces after all.
This animation shows the amount of light detected by each pixel in a small section of the camera onboard NASA’s Kepler space telescope. The light collected from TRAPPIST-1 is at the center of the image. NASA Ames/G. Barentsen
Another team of astronauts led by astronomer Krisztián Vida from Konkoly Observatory in Hungary has been analyzing luminosity patterns of TRAPPIST-1. During the 80 days of observation, they noticed 42 high-energy flares blasting from the start. One eruption was particularly strong, similar to the most famous solar storm known as the Carrington Event of 1859. To stabilize the planet’s atmosphere from extreme star flares, it would take 30,000 years. On the other side, planets in the Trappist-1 system are hit by flares every 28 hours.
Being so close to the host star and continually bombarded probably destroy stability in the atmosphere, leaving no time for recovery and possibilities to return to a steady state. Such a volatile system couldn’t be a host even to the most primitive life forms. To turn things around and being protected, the planets should develop magnetosphere of tens to hundreds of Gauss ( Earth’s magnetosphere is only about 0.5 Gauss ), which is impossible.
Yes, things sound depressing now. Although we can’t be so enthusiastic as before, we still have a right to hope. Perhaps the Trappist-1 is weird enough to surprise us once more.