Astronomers Detect Decagonal Atmospheric Wave on Saturn

Astronomers have discovered an unusual decagonal-shaped atmospheric wave on Saturn. This finding, based on observations, suggests that the wave may still be evolving, representing a dynamic phenomenon in the gas giant's atmosphere. The decagonal shape is particularly noteworthy, as polygonal structures in planetary atmospheres are rare and offer clues about complex fluid mechanisms and large-scale atmospheric dynamics. This discovery adds to the understanding of Saturn's complex atmospheric dynamics, a planet known for its unique meteorological features, such as the famous polar hexagon at its north pole. While the hexagon is a well-studied and relatively stable structure, the identification of an evolving decagonal wave introduces new questions about the processes that can generate and maintain such geometric patterns. Future research will focus on determining the exact mechanisms shaping this wave and how it interacts with other atmospheric features of the planet. The observation of this decagonal wave provides crucial data for planetary atmospheric dynamics models. The ability to observe these structures in real or near-real time allows scientists to refine their theories on vortex formation, wave propagation, and energy transfer in giant atmospheres. Understanding the evolution of this decagonal wave could shed light on similar phenomena on other gas planets and even on Earth, where atmospheric waves play a fundamental role in climate and weather patterns.

Sagittarius A* Could Be a Galactic PeVatron via Magnetic Penrose Process

Researchers have explored the Magnetic Penrose Process (MPP) as an efficient mechanism for extracting rotational energy from magnetized Kerr black holes, enabling charged particles to reach very-high energies. The study focuses on Sagittarius A* (Sgr A*), the supermassive black hole at the Galactic Center, and its ability to accelerate protons up to PeV (petaelectronvolt) energies, strengthening its interpretation as a candidate Galactic PeVatron. The key novelty of this research lies in the direct computation of the neutron production spectrum in Sgr A*'s accretion flow, derived from nuclear reaction kinematics. Subsequently, the trajectories of these neutrons in Kerr spacetime are traced to identify those that reach the black hole's ergosphere and undergo the MPP. From this population, the spectrum of accelerated protons is derived, demonstrating that Sgr A* can boost these particles to PeV energies. The team also computed the gamma-ray and neutrino emission resulting from hadronic interactions of the escaping protons in the Central Molecular Zone. The predicted gamma-ray fluxes exhibit distinctive spectral features that could provide an observational signature of the MPP, potentially making a non-negligible contribution to the very-high-energy emission detected by H.E.S.S. and HAWC. While the associated neutrino fluxes remain below the diffuse Galactic component inferred by IceCube, they may still contribute to the high-energy emission from the Galactic Center. The predicted signals lie within the projected sensitivity of SWGO and, for some models, are only a factor of a few below the nominal CTAO sensitivity, with KM3NeT/ARCA and IceCube-Gen2 providing complementary tests. These results establish the MPP as an observable mechanism for extracting black hole rotational energy, providing a direct connection between horizon-scale physics and multimessenger observations. This approach can be extended to study other magnetized black holes, opening new avenues for understanding the universe's most extreme particle acceleration processes.