Scientists have used the “perfect harmony” of a distant planetary system to learn more about its past.
The star Trappist-1 is best known for being the centerpiece of what NASA calls the “Holy Grail” solar system, which looks remarkably similar to Earth. Since the discovery was first announced in 2017, astronomers have found even more information about the system, including that it contains more planets and could be a home for life.
However, scientists are still discovering more about these worlds, even though they are very different from Earth. In recent research, astronomers have used the “near perfect harmony” of the orbits of the seven planets in the Trappist 1 system to better understand their past.
The harmony refers to the amazing cleanliness of the orbits of the various planets in the system. They are organized in precise relationships, similar to the arrangement of harmonic musical notes: every eight years on one planet, five years pass on the next, and they continue in such precise relationships.
The new research allows scientists to better understand the impact history of these planets or what crashes they may have experienced in their childhood. This can help better characterize whether planets might have the water and other materials necessary for life to begin.
“After rocky planets form, things collide with them,” said astrophysicist Sean Raymond of the University of Bordeaux in a statement. “It’s called bombing, or late accretion, and we care in part because those strikes can be an important source of water and volatile elements that promote life.”
Studying these impacts on Earth is difficult enough and must be done by measuring certain elements and comparing them to the composition of meteorites. This is clearly impossible in a system 40 light-years away like Trappist-1 – and the scientists therefore had to rely on more complex methods.
“We’ll never get stones from them,” said Raymond. “We’ll never see craters on them. So what can we do This is where the special orbital configuration of TRAPPIST-1 comes into play. It’s a kind of lever that we can pull to set limits. “
The researchers were able to estimate how much bombardment the planets could have undergone before being knocked out of this orderly and resonant harmony. That helps to find out what could have happened to these planets.
“We can’t say exactly how much stuff hit any of these planets, but because of this particular resonance configuration, we can set an upper limit,” said Raymond. “We can say: ‘It couldn’t have been more.’ And it turns out that this cap is actually pretty small.
“We found that these planets were not bombarded by more than a very small amount of material after they formed,” he said. “It’s kind of cool. It is interesting information when we think about other aspects of the planets in the system. “
The results will help scientists tell the story of the Trappist 1 planets. They must have formed early and quickly – about ten times faster than Earth – but not have been bombed too much, which helps to understand what might be in these worlds and how their atmosphere might have formed.
However, scientists are finding that there is much more to be learned about the system. Future research through projects like the upcoming James Webb Space Telescope could help get rid of some of the unknowns in the new research.