On 3 May 2016, a team of professors and students at the University of Liège in Belgium discovered three potentially habitable planets orbiting around an ultracool dwarf star about forty light years away from Earth.
Even though forty light years means that the planets would take millions of years to reach from Earth with current human technology, the planets are closer than many other potentially habitable worlds that have previously been identified.
Julien de Wit, a postdoctoral researcher in the Department of Earth, Atmospheric, and Planetary Sciences at the University of Liège, stresses the importance of making further investigations in an MIT News article.
“These planets are so close, and their star so small, we can study their atmosphere and composition, and further down the road, which is within our generation, assess if they are actually inhabited,” said de Wit. “All of these things are achievable, and within reach now. This is a jackpot for the field.”
Usually, ultracool dwarf stars do not hold promising prospects for the existence of life. No habitable planets were found around a sun so small and dim in the past. Emmanuël Jehin, a research associate on the group that discovered the planets, summarizes the uniqueness of the discovery in an article by the European Southern Observatory.
“This really is a paradigm shift with regards to the planet population and the path towards finding life in the Universe,” said Jehin. “So far, the existence of such ‘red worlds’ orbiting ultracool dwarf stars was purely theoretical, but now we have not just one lonely planet around such a faint red star but a complete system of three planets!”
This discovery was not made by NASA, the European Space Agency, or another large organization, but rather by a team of professors, researchers, and students centered out of the University of Liège called Trappist. They used their telescope for 62 nights to observe the star 2MASS J23062928-0502285, also known as TRAPPIST-1.
The Trappist team discovered the planets using TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope), which is a 60-centimeter telescope operated by the University of Liège and located in Chile. TRAPPIST is designed to focus on 60 nearby dwarf stars, which are very small, cool, and are so faint they are invisible to the naked eye.
The group was studying one of the stars and found that it faded very slightly at regular intervals, indicating that several objects were passing between the star and the Earth. Analysis showed that there were three planets about the size of Earth orbiting it, and were further able to determine that the three planets have orbital periods of about 1.5 (Earth) days, 2.4 days, and between 4.5 and 73 days.
Michaël Gillon, a research associate at the University of Liège and key member of the Trappist team, explains this information in terms of planets closer to home.
“With such short orbital periods, the planets are between 20 and 100 times closer to their star than the Earth to the Sun,” said Gillon. “The structure of this planetary system is much more similar in scale to the system of Jupiter’s moons than to that of the Solar System.”
According to Gillon the full project will now focus upon the planets that the team uncovered and their atmospheres.
“We will use bigger telescopes with more sensitive instruments to explore more,” said Gillon “We are looking for planets that could have on their surfaces the conditions like on Earth and may host life.”
Further investigations could prove whether or not life exists on one or more of the planets, potentially answering the question of whether or not we are alone in the universe.