Clouds and Hazes in the Atmospheres of Triton and Pluto

TL;DR

This paper reviews observational evidence, theoretical models, and laboratory experiments related to clouds and hazes in the cold atmospheres of Triton and Pluto, highlighting their chemical processes and impact on surface and atmospheric evolution.

Contribution

It provides a comprehensive synthesis of current knowledge and experimental approaches to understanding clouds and hazes on Triton and Pluto, which is novel in integrating observations, theory, and lab work.

Findings

Presence of complex hydrocarbons and nitriles in atmospheres

Laboratory experiments replicating cloud and haze formation

Impacts on atmospheric chemistry and surface evolution

Abstract

Clouds and hazes are abundant in the thin and cold atmospheres of Triton and Pluto, where they are thought to be produced by interactions between atmospheric gases and ultraviolet photons from the Sun and those scattered by the local interstellar medium. These interactions lead to a rich network of chemical reactions that produces higher order hydrocarbons and nitriles that condense out to form ice clouds, and ultimately complex haze particles that rain down onto the surface that impact the atmospheric thermal structure, gas chemistry, and surface evolution. In this chapter, we will review the observational evidence for clouds and hazes in the atmospheres of Triton and Pluto and theoretical interpretations thereof, and the emerging set of experiments aiming to produce Triton and Pluto clouds and hazes in the lab to learn about them in detail.