Seven Earth-sized Planets orbit the star TRAPPIST-1 in near-perfect harmony, and U.S. and European researchers have used that harmony to determine how much physical abuse the could have withstood in their infancy.
Sean Raymond of the University of Bordeaux in France and Astrophysicist said that after rocky Planets form, things bash into them. This is called bombardment, or late accretion, and we care about it, in part, because these impacts can be an important source of water and volatile elements that foster life.”
Those tools don’t exist for studying bombardment on exoplanets.TRAPPIST-1, about 40 light-years away, is far smaller and cooler than our sun. Its Planets are named alphabetically from b to h in order of their distance from the star. The time needed to complete one orbit around the star—equivalent to one year on Earth—is 1.5 days on b and 19 days on Planets h. Their orbital periods form near-perfect ratios, a resonant arrangement reminiscent of harmonious musical notes. For example, for every eight “years” on b, five pass on c, three on d, two on e and so on.