Currently, the number of confirmed exoplanets stands at 5,197 in 3,888 planetary systems, with a further 8,992 candidates awaiting confirmation.
Most were particularly massive planets, from gas giants the size of Jupiter and Neptune, which have radii about 2.5 times that of Earth. Another statistically significant population was represented by rocky planets measuring about 1.4 Earth radii (“Super-Earths”).
This is a mystery to astronomers, especially regarding the exoplanets discovered by the venerable Kepler space telescope.
Of the more than 2,600 planets discovered by Kepler, there is an apparent rarity of exoplanets with a radius of about 1.8 times that of Earth – which they refer to as the “radius valley”.
The number of confirmed exoplanets stands at 5,197
A second mystery concerns similar-sized neighboring planets found in hundreds of planetary systems with harmonious orbits, writes Inver.
In a study led by Rice University, a team of astrophysicists offers a new model that explains the interplay of forces acting on newborn planets that could explain these two mysteries.
As they describe in their research paper, recently published in Astrophysical Journal Lettersthe team used a supercomputer to run a planetary migration model that simulated the first 50 million years of planetary system development.
In their model, protoplanetary disks of gas and dust also interact with migrating planets, pulling them closer to their parent stars and locking them into resonant orbital chains.
New opportunities for exoplanet researchers
Within a few million years, the protoplanetary disk disappears, breaking the chains and causing orbital instabilities that cause two or more planets to collide.
While models of planetary migration have been used to study planetary systems that have preserved orbital resonances, these findings are a first for astronomers.
Their results indicate that the collisions in the TRAPPIST-1 system were comparable to the impact that created the Earth-Moon system.
These discoveries present opportunities for exoplanet researchers, who will rely on the James Webb Space Telescope to conduct detailed observations of exoplanet systems.
With its advanced suite of optics, infrared imaging, coronagraphs and spectrometers, Webb and other next-generation telescopes will characterize the atmospheres and surfaces of exoplanets like never before.