Research

Astronomers continue to wonder about the habitability of the TRAPPIST-1 planetary system

Perhaps one of the most interesting planetarysystems open lately is the TRAPPIST-1 system. Located “only” 40 light years from Earth, it is home to seven earth-like planets wrapping around a small red dwarf star. Astronomers believe that the three planets of the system are located in the so-called habitable zone of the star. Immediately, two new studies were aimed at understanding the habitability of these three worlds. Scientists have paid special attention to the level of radiation of a star, affecting these planets, as well as the tidal forces of the planets-neighbors. As it turned out, these two factors increase the chances of the existence of life on the three planets discussed.

One of the oddities of this system isthat all seven of her planets, named from TRAPPIST-1b to -1h, are in orbit in close proximity to the star and from each other. In other words, they could well fit in the space between Mercury and the Sun. At first glance, it can show that such a proximity to a star would be fatal for life, but fortunately, TRAPPIST-1 is a relatively cold red dwarf, so the radius of its habitable zone is much lower than that of the same Sun.

The problem is that the starTRAPPIST-1 is very active. It ejects much more high energy particles than our sun. This radiation can destroy the complex molecules necessary for the origin and development of life.

Radiation of a red dwarf

One of the studies was devoted to modelingthe motion of high-energy particles (protons) after their emission by the star TRAPPIST-1. Scientists modeled their interaction with the luminous magnetic field and found that the bulk of these protons would bombard the fourth planet of the system, TRAPPIST-1e. Unfortunately, it is she who is considered by researchers as the most likely candidate for habitability.

"These particles must be held up by magneticfield, but if we introduce the factor of turbulence, the protons can leave the magnetic field. The direction of motion of the particles depends on how the star's magnetic field deviates from its axis of rotation. This stream of particles can be a million times more intense than the one that hits the magnetic field of our planet, ”says Frederico Fraschetti, lead author of the study.

Our Earth has a magnetic field, whichprotects us from the effects of these high-energy particles. Scientists have suggested that the planets TRAPPIST-1e may also have a magnetic field, although in order to effectively protect the surface of a planetary object in this case, it will need a 100 times stronger magnetic field than our Earth has. And this, scientists say, is unlikely.
At the same time, experts do not believe that suchstate of affairs automatically excludes the possibility of life on this planet. In other studies, it has been suggested that some of the planets of the TRAPPIST-1 system may be aquatic worlds, and their deep oceans can protect underwater life from the effects of this powerful radiation.

Tidal grip

In addition, scientists believe that the planetsTRAPPIST-1 is probably tidal locked. On the one hand, this means that the same hemisphere of each planet always faces the star, while eternal night envelops the other side.

On Earth, the Moon raises tides not only inoceans. Tidal forces deform the spherical shape of the mantle and crust. In the TRAPPIST-1 system, the two closest to the star planets are located close enough to each other, so scientists have suggested that the worlds can cause tides at each other, like the Moon to Earth. At the same time tidal forces can be so powerful that they are capable of maintaining volcanic activity on both space bodies. This, in turn, allows you to save the atmosphere on both planets.

Researchers also believe that the sixth planetthe system, TRAPPIST-1g, is also subject to tidal forces of neighbors. If this planet is the ocean world, as suggested in other studies, this tidal effect can also keep the temperature of the water on the planet high enough for life to exist in it.

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