Strange mystery of ‘missing’ planets in space can be solved: ScienceAlert
Today the number of confirmed exoplanets is up 5,197 in 3,888 planetary systemswith a further 8,992 candidates pending confirmation.
Most were particularly massive planets, ranging from Jupiter and gas giants the size of Neptune, which have a radius about 2.5 times that of Earth.
Another statistically significant population is rocky planets measuring about 1.4 Earth radii (also known as ‘super-Earth’).
This is a mystery to astronomers, especially where the exoplanets discovered by the venerable Kepler Space Telescope are concerned.
Of the more than 2,600 planets Kepler discovered, there is an apparent rarity of exoplanets with a radius about 1.8 times Earth’s — which they call the “radius valley.”
A second mystery, known as “peas in a pod,” refers to neighboring planets of similar size found in hundreds of planetary systems with harmonious orbits.
In a study led by the Cycles of life-essential volatile elements in rock planets (CLEVER) project at Rice University, an international team of astrophysicists offers a new model that explains the interplay of forces acting on newborn planets that could explain these two mysteries.
The research was led by André Izidoro, a Welch postdoctoral researcher at Rice’s NASA-funded SMART planets project. He was joined by fellow CLEVER Planets researchers Rajdeep Dasgupta and Andrea Isella, Hilke Schlichting from the University of California, Los Angeles (UCLA), and Christian Zimmermann and Bertram Bitsch from the Max Planck Institute for Astronomy (MPIA).
As they describe in their research paper, which appeared recently in the Astrophysical Journal Lettersthe team used a supercomputer to run a planetary migration model that simulated the first 50 million years of planetary systems 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 in resonant orbital chains.
Within a few million years, the protoplanetary disk disappears, breaking the chains and causing orbital instabilities that cause two or more planets to collide. Although planetary migration models have been used to study planetary systems that conserve orbital resonances, these findings represent a first for astronomers.
As Izidoro said at a Rice University pronunciation: “I believe we are the first to explain the radius valley using a model of planet formation and dynamic evolution that is self-consistently responsible for multiple limitations of observations.
“We can also show that a planet formation model with giant impacts is consistent with the peas-in-a-pod function of exoplanets.”
This work builds on previous work by Izidoro and the CLEVER Planets project. Last year, they used a migration model to calculate the maximum perturbation of TRAPPIST-1’s seven-planet system.
In a newspaper that appeared on November 21, 2021 in Natural Astronomy, they used N-body simulation to show how this “peas in a pod” system could have kept its harmonious orbital structure despite collisions caused by planetary migration. This allowed them to set limits on the upper bound of collisions and the mass of the objects involved.
Their results indicate that collisions in the TRAPPIST-1 system were similar to the impacts created by the Earth-Moon system.
Izidoro said: “The migration of young planets to their host stars causes overpopulation and often results in catastrophic collisions that strip planets of their hydrogen-rich atmospheres.
“That means that giant impacts, such as those that formed our moon, are likely a general result of planet formation.”
This latest research suggests that planets come in two varieties, consisting of dry and rocky planets that are 50 percent larger than Earth (super-Earth) and planets rich in water ice, about 2.5 times the size of Earth (mini-Neptune). ).
In addition, they suggest that a fraction of the planets twice the size of Earth will retain their original hydrogen-rich atmosphere and be rich in water.
According to Izidoro, these results are consistent with new observations that suggest that super-Earth and mini-Neptune are not exclusively dry and rocky planets.
These findings provide opportunities for exoplanet researchers, who will rely on the James Webb Space Telescope to conduct detailed observations of exoplanet systems.
Using its advanced array of optics, infrared imaging, coronagraphs and spectrometers, Webb and other next-generation telescopes will characterize the atmospheres and surfaces of exoplanets like never before.
#Strange #mystery #missing #planets #space #solved #ScienceAlert