Can Triton's Internal Heat Be Inferred From Its Ice Cap?

Abstract

AbstractNeptune's moon Triton is among the Solar System's most geologically active bodies, allowing for study of its internal dynamics through surface features. Here, I consider whether the unusually great extent of its nitrogen ice cap constrains its geothermal heat. I find that viscous spreading alone can result in a hemispheric‐scale ice sheet, which only yields a loose constraint on geothermal heat flow ≥2 mW/m2. However, if the ice cap's great extent is additionally aided by basal melting, heat flow would be constrained between 5 and 18 mW/m2. This latter range would require a significant heat source beyond radiogenic heating and be sufficient to drive vigorous geological activity, providing an explanation for the moon's youthful surface and strengthening the case for Triton as an ocean world. High‐resolution images and topographic data from a new spacecraft mission at Triton would allow for testing of these possibilities and constraints on the moon's internal heat.