Star System Offers Hope for Life

This artist’s impression shows the view from the surface of one of the planets in the TRAPPIST-1 system. At least seven planets orbit this ultra cool dwarf star 40 light-years from Earth and they are all roughly the same size as the Earth. They are at the right distances from their star for liquid water to exist on the surfaces of several of them. This artist’s impression is based on the known physical parameters for the planets and stars seen, and uses a vast database of objects in the Universe.

Artist’s rendering of the TRAPPPIST-1 system. Depicted are the seven planets and their parent star.

Vittorio Colicci ’18
EE Staff Writer

Since the discovery of the first exoplanet back in 1992, the search for planets beyond our solar system has been on.
Large telescopes set up across and around the globe comb the sky for any candidates potentially harboring alien life. It was using one of these telescopes that scientists, on February 22, announced the discovery of a 7-planet star system named TRAPPIST-1, located about 40 light years away.

This system is special not only because of its record-breaking number of worlds, but also due to the fact that each of them appear to be rocky, similar in size and density to our own. Among the TRAPPIST-1 planets, 3 are even thought to be located within the star’s habitable zone, where liquid water could theoretically exist.

Of course, there are factors that could stand in the way of any evolution of life. The system’s parent star, an ultra-cool red dwarf, may yield conditions entirely different from those of our Sun. Though it has a radius 11% of that of the Sun, TRAPPIST-1’s luminosity (the intensity of the light it emits) is a mere .05%. Its planets would need to be in far closer orbits to receive a sustainable amount of stellar radiation.Given the nature of red dwarfs, this poses an issue.

Studies have shown a tendency for intense radiation storms, with solar flares spiking the energy dosage received by any surrounding planets. Life would not be able to adapt to such extreme fluctuations, and atmospheres would likely be stripped away by solar wind. Observations have additionally indicated the likelihood of tidal locking among the TRAPPIST-1 planets.

As is present with the Earth and Moon, tidal locking occurs when the same side of an astronomical body constantly faces whatever it orbits. This is why we never see the “dark side” of the Moon. For planets, however, the implications are more severe.

The lack of a day/night cycle would cast one hemisphere in perpetual light and the other in darkness, causing wild differences in temperature. If life were to exist, the most favorable environment would be within the band that separates the two, where a more moderate climate persists.

Ultimately, the true indication of life in the star system will come with the detection of bioindicators within its planetary atmospheres.

In October 2018, the James Webb Telescope is expected to be completed. Hopefully, this will finally shed light on whether we truly are alone in the universe.

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