An international research team led by a University of Washington astronomer has worked out the intricate dance of seven planets circling an ultracool dwarf star known as TRAPPIST-1, nailing down the coordinates of the outermost world in the process.
The astronomers found that all seven exoplanets follow stable orbits thanks to a regular pattern of gravitational interactions, known as orbital resonance. And they determined conclusively that the seventh planet, called TRAPPIST-1h, is too cold for life – although it was could have been warmer in its ancient past.
The calculations, laid out today in the journal Nature Astronomy, will go down as another success story for the planet-hunting process.
