The researchers note in their paper that "there should be a large but hitherto undetected population of terrestrial planets orbiting" ultra-cool dwarves, "ranging from metal-rich Mercury-sized planets to more hospitable, volatile-rich, Earth-sized planets."
The team found the planets using the Trappist telescope, an optical system located in Chile but operated robotically from a control center in Belgium.
David Kipping, an astronomer at Columbia University who was not involved with the research, told the New Scientist that there "is a legitimate case to be made that this system could host life, and we may be able to infer the presence of that life in the next decade."
But not everyone is convinced the planets are habitable.
San Diego State University astronomer Jerome Orosz, told KPBS that two of the planets receive two to four times the amount of radiation Earth does, which "seems high."