A team of scientists has discovered six exoplanets orbiting a star called HD 110076, and what's interesting about these exoplanets is that they are in a rare phenomenon known as a chain of resonance.
So, what is a chain of resonance? This phenomenon occurs when two bodies orbiting a third body interact with each other gravitationally, and their orbital periods line up. Notably, these orbital periods don't have to line up 1:1. An example of this phenomenon is Pluto and Neptune - Pluto completes 2 orbits around the Sun for every 3 of Neptune's, creating a resonance of 2:3. Another example is some of Jupiter's moons such as Ganymede, Europa, and Io. For every 1 of Ganymede's orbits, Europa completes 2 orbits and Io 4 orbits, creating a 1:2:4 chain.
Using telescope's, the researchers discovered six exoplanets that vary in size from 1.94 to 2.85 times the size of Earth. As for their orbital periods; 9.11 days, 13.67 days, 20.52 days, 30.79 days, 41.06 days, and 54.77 days (from the innermost exoplanet to the outermost). Their chain of resonance is as follows: 3:2, 3:2, 3:2, 4:3, and 4:3. This discovery marks just the sixth system known to date with six exoplanets in a chain of resonance, and due to the chain of resonance still being untouched, it represents a region of space that has hardly been influenced by outside forces such as asteroid impacts and planetary migration.
"The current delicate configuration of the planetary orbits in HD 110067 rules out any violent event over the billion-year history of the system, making it a rare 'fossil' to study migration mechanisms and the properties of its protoplanetary disk in a pristine environment," write the researchers.