GEOPHYSICAL, GRA VITATIONAL, AND MAGNETIC DATA ON NEPTUNE'S MOON TRITON

Abstract

Neptune's largest satellite, Triton, moves in a retrograde orbit with an inclination of the orbital plane to the equator of Neptune close to 157°. Such parameters indicate that Triton is a captured object formed in the outer regions of the protoplanetary disk. Interaction with Neptune's gravitational field caused enormous tidal deformations in the satellite's body, which were accompanied by the release of a huge amount of heat. This tidal heating initiated a deep gravitational differentiation of matter into a metal core, a silicate mantle, and an ice shell. Analysis of the refle ction spectra of the opposite hemispheres of Triton revealed a pronounced longitudinal asymmetry in the distribution of the most volatile substances. And less volatile compounds are thermodynamically stable at the average surface temperature of Triton ~ 38 K and are distributed extremely evenly over the surface and do not show significant long-term fluctuations. The relative contributions of carbon and nitrogen compounds in Triton's surface ices and atmosphere suggest a long- term influence of endogenous water processes. On Triton, much of the primary methane was chemically reprocessed by hydrothermal synthesis in the subsurface ocean. Thermal and geodynamic models suggest that after an era of extreme tidal heating, Triton's metallic Fe-FeS core could have retained enough heat to sustain convection to the present day. Voyager 2 data clearly indicate that Triton's surface is extremely young. The average age of surface structures is no more than 10–100 million years, and some regions of active cryovolcanism are even younger, less than 6–10 million years. Additional evidence for a long- term internal heat source comes from chemical tracers obtained from volatile compounds on Triton's surface. High- precision infrared spectroscopy confirmed the presence of a complex volatile and non- volatile cover, revealing anomalously deep carbon dioxide bands, signs of complex organic compounds, and atmospheric CO fluorescence. This indicates long- term endogenous and photochemical processes. The young surface age of Triton confirms its modern geological and cryovolcanic activity.