Short answers, pulled from the story.
Astronomer John Gizis published the first detection of TRAPPIST-1 in 2000, though observations from June 1999 had already captured its light. The star remained an obscure red dwarf for sixteen years before a team led by Belgian astronomer Michaël Gillon changed everything.
Seven planets now circle this dim sun, taking between 1.5 and 19 days to complete their orbits. These seven bodies lie in nearly the same plane with orbital inclinations differing by less than 0.1 degrees while moving in highly circular paths.
TRAPPIST-1 burns with a spectral class of M8V and maintains a surface temperature around 2,550 Kelvin. Its radius measures only 12% of the Sun's size yet remains slightly larger than Jupiter itself.
International teams used the Spitzer Space Telescope alongside ground-based instruments like the Liverpool Telescopes in Spain and the Himalayan Chandra Telescope to confirm these findings. Observations from the James Webb Space Telescope indicate cold spots cover up to one quarter of the stellar surface.
Three or four planets lie within the habitable zone where liquid water could persist depending on atmospheric conditions. TRAPPIST-1e stands as the most likely candidate to retain water equivalent to several Earth oceans despite intense stellar radiation.