(ORDO NEWS) — Studying the structure of the interior of the ice giants of the solar system is difficult, since the thick ice shell does not allow one to see the inner parts of the planets.
In a new study, a team of scientists led by Joseph A. A “Hearn from the University of Idaho, USA, proposed a new method for studying the structure of the interior of Uranus and Neptune, based on the analysis of the rings of giant planets.
This is not the first indirect method used by scientists to study the interior of giant planets. Previous studies have attempted to use a common photometric method to detect oscillations on planetary surfaces.
These oscillations could then be correlated with the density of individual parts of the planetary interiors. Although this method worked effectively in the case of Jupiter, in the case of ice giants, the available photometric data turned out to be insufficient to construct similar density profiles.
The alternative is to use gravitational oscillations propagating beneath the surface of the planet. In particular, one of the modes of such oscillation is known as the normal mode.
This oscillation mode is established when all parts of the system begin to oscillate with the same sinusoidal frequency. Gravitational effects associated with the normal mode of oscillations in the interior of the planet are available for registration from the outside and are reflected in the structure of the planet’s rings.
This method has already been successfully used previously for the Saturn system, but in a new study, it was first applied to the study of the structure of the interior of ice giants.
In their new study, Ahern and his team analyze the behavior of density waves in the rings of ice giants, which resonate with gravitational oscillations that occur in the interior of these planets.
In addition, the researchers note that the extreme inner “shepherd satellites” of the planets (satellites clearing space in the gaps between the rings) are affected by the same resonances. Some of these satellites can even form their own resonances, known as Lindblad resonances.
Typically, Lindblad resonances are more often observed at the scale of galaxies, in which case they give rise to spiral density waves that lead to the formation of “sleeves” that are clearly visible in many spiral galaxies.
But on a smaller scale, similar phenomena are observed for planetary ring systems, including Saturn and probably also Uranus and Neptune.
The problem with using these resonances, which are reflected in the structure of the rings, is the lack of observational data.
So, to date, no spacecraft has spent enough time in orbit around the ice giants to collect the required amount of information about their ring systems.
The authors of the work and many other researchers believe that the time has come to send a new probe to the ice giants to compile a detailed map of the structure of the ring system, as well as determine the exact location of the satellites of the planets and a large number of other objects discovered in recent years that are difficult to observe from Earth.
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