An international group of astronomers announced the discovery of a stellar system with 7 planets with a mass similar to ours, 3 of which are in a habitable zone and could harbor oceans of water on their surface. The planets are located 40 light years from Earth, in the constellation Aquarius. They orbit around Trappist-1, a “low” mass and “cold” star.
The star and the system that revolves around it are called Trappist for the Small Telescope for Transiting Planets and Planetesimals, located in Chile. With this instrument, 3 of the 7 planets were observed, in May 2016, according to the NASA page.
What is known about that stellarsystem
Due to its conditions, there is a possibility that the Trappist-1 system could host life. Three of these worlds are within a zone considered “habitable”, due to the distance that separates them from their star.
But project co-investigator AmauryTriaud of the University of Cambridge, UK, said that if the outermost planet has an atmosphere that efficiently traps heat -a bit more like Venus’s atmosphere than Earth’s- it could be habitable. “It would be disappointing if Earth represents the only possibility for habitability in the Universe”,Triaud said.
Is it a new Earth?
“Finding a new Earth is a matter of time”, said astrophysicist Thomas Zurbuchen. He is NASA’s director of space missions during the announcement of the discovery via Facebook.
NASA has produced a futuristic travel poster to the Trappist-1 system. “Voted Best Destination Within 12 Parsecs (measurement equivalent to 3.26 light-years) from Earth”, reads the fictional ad. MichaëlGillon, an astronomer at the University of Liège, Belgium, and principal investigator of the project, said that “the planets are very close to each other and very close to the star, which is very reminiscent of the moons around Jupiter”.
In fact, all 7 planets are closer to Trappist-1 than Mercury is to the Sun, according to NASA. If a person were to stand on the surface of one of them, he might sight one of the other planets, much like the Moon is seen from Earth. “However, the star is so small and so cold that all 7 planets are temperate, which means they could have liquid water and, by extension, perhaps life on their surfaces”, he added.
The discovered system has both the largest number of Earth-sized planets and the largest number of worlds that could have surface liquid water found to date. The planets, the discovery of which appeared in the journal Nature, were detected using NASA’s Spitzer Space Telescope and several ground-based observatories.
The 6 inner planets appear to have coordinated orbits with each other. This harmonization appears to be the result of interactions early in the evolution of the planetary system.
In the search for oxygen
The next phase of the research is to look for key gases such as oxygen and methane, which could provide evidence about what happens on the surface, explains David Shukman, BBC Science editor. “The excitement around this latest discovery stems not only from the fact that many of the planets are the size of Earth.
“Also, since the Trappist-1 star is conveniently small and dim. This means that the telescopes will not be ‘dazzled’ as they would be when pointing at much brighter stars”,Shukman says. “Thus, a fascinating avenue of investigation of these worlds and their atmospheres opens up”, he adds.
Astronomers confirm that it should be possible to study the atmospheric properties of planets with telescopes. “The James Webb Space Telescope, the successor to Hubble, will have the possibility of detecting ozone if this molecule is present in the atmosphere of any of the worlds”, said study co-author Brice-Olivier Demory of the University of from Bern, Switzerland. “(Ozone) could be an indicator of biological activity on the planet”, he added.
But the astrophysicist also warns that we must be extremely careful when inferring biological activity from afar. Some of the properties of cool, low-mass stars could pose challenges for the development of life. For example, some are known to emit large amounts of radiation in the form of flares, which has the potential to sterilize the surfaces of nearby planets.