Not long ago, scientists announced the discovery of a star system with THREE planets located in the so-called habitable zone of their star system, a mere 40 light years away from Earth.
Now, a new study published in the Journal Science reveals fascinating details about the planets of the star system.
In May 2016, scientists at the Massachusetts Institute of Technology (MIT) and the University of Liege in Belgium, announced the discovery of three planets of similar size of Earth and potentially habitable located just 40 light years from Earth, orbiting a dwarf star.
Now, in a new article published in the journal Nature, the same group of scientists reported that the two inner planets in the system are rocky, like ours, a fact that reinforces the possibility that these worlds could harbor life. Researchers have also determined that the atmospheres of both planets seem to be compact and similar to those of Earth, Venus, and Mars.
Scientists came to the conclusion after they used the Hubble Space Telescope to spy at the star system deducing that the innermost planets of the star system are rocky like our own and are encompassed by a compact atmosphere similar to that of Earth.
But even before taking a peek at the star system with Hubble, researchers concluded that based on the size and temperature of the three planets, they may be one of the best candidates to harbour life, ever discovered in the universe.
The three alien worlds are orbiting a super cool Brown Dwarf Star about one-eighth the size of our Sun. The Star is known as Trappist-1.
According to researchers, and based on new studies, the two innermost worlds orbit in 1.5 and 2.4 days while the orbit of the third planet is more uncertain and could be anywhere from four days to seventy-three days.
The discovery of the alien worlds was made possible after Michaël Gillon of the University of Liège, Belgium, and his team set up the Trappist survey specifically aimed at scanning the 60 closest dwarf system to Earth.
In a statement, Gillon said that: „Systems around these tiny stars are the only places where we could detect life on Earth-sized exoplanets with our current technology. So this is where we should start to look.“
To make the discovery, the group of researchers observed how the light emitting from the star dipped as the planets made their way in front of it in a number of different wavelengths.
According to researchers, if the dips varied significantly as the observational wavelengths carried, this would have meant that the planets have lighter, larger and puffy-like atmosphere similar to that found on Jupiter.
However, the dips remained relatively constant which demonstrated that both rocky planets have extremely compact atmospheres comparable to those of Venus, Earth, and Mars.
„Now we can say that these planets are rocky. ‘Now the question is, what kind of atmosphere do they have?“ Dr. Julien de Wit, the lead author of the paper, said.
„The plausible scenarios include something like Venus, where the atmosphere is dominated by carbon dioxide, or an Earth-like atmosphere with dense clouds, or even something like Mars with a depleted atmosphere. The next step is to try to disentangle all these possible scenarios that exist for these terrestrial planets.“
“A rocky surface is a great start for a habitable planet, but any life on the TRAPPIST-1 planets is likely to have a much harder time than life on Earth,” says Joanna Barstow, an astrophysicist at University College London, who was not involved with the research.
The next step is to understand the alien planets more, and in order to do so, they hope to point larger ground-based telescopes ni their direction in addition to further observations performed from space.
“With more observations using Hubble, and further down the road with James Webb, we can know not only what kind of atmosphere planets like TRAPPIST-1 have but also what is within these atmospheres,” de Wit says. “And that’s very exciting.”