Discovery of fog at the south pole of Titan

Abstract

While Saturn's moon Titan appears to support an active methane hydrological cycle, no direct evidence for surface-atmosphere exchange has yet appeared. It is possible that the identified lake-features could be filled with ethane, an involatile long term residue of atmospheric photolysis; the apparent stream and channel features could be ancient from a previous climate; and the tropospheric methane clouds, while frequent, could cause no rain to reach the surface. We report here the detection of fog at the south pole of Titan during late summer using observations from the VIMS instrument on board the Cassini spacecraft. While terrestrial fog can form from a variety of causes, most of these processes are inoperable on Titan. Fog on Titan can only be caused by evaporation of liquid methane; the detection of fog provides the first direct link between surface and atmospheric methane. Based on the detections presented here, liquid methane appears widespread at the south pole of Titan in late southern summer, and the hydrolgical cycle on Titan is current active.

submitted to ApJL

References in corpus (1)

• Discovery of lake-effect clouds on Titan

Cited by in corpus (8)

• Evidence of Titan's Climate History from Evaporite Distribution
• The near-surface methane humidity on Titan
• Meridional variation in tropospheric methane on Titan observed with AO spectroscopy at Keck and VLT
• Air-Sea Interactions on Titan: Lake Evaporation, Atmospheric Circulation, and Cloud Formation
• The impact of lake shape and size on lake breezes and air-lake exchanges on Titan
• Air-sea interactions on Titan: effect of radiative transfer on the lake evaporation and atmospheric circulation
• Possible ground fog detection from SLI imagery of Titan
• Science goals and new mission concepts for future exploration of Titan's atmosphere geology and habitability: Titan POlar Scout/orbitEr and In situ lake lander and DrONe explorer (POSEIDON)