The case for seasonal surface changes at Titan’s lake district - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Nature Astronomy Année : 2019

The case for seasonal surface changes at Titan’s lake district

Résumé

Titan, Saturn's largest moon, hosts lakes and seas of liquid hydrocarbons at its poles 1. General circulation models demonstrate that regional evaporation and precipitation rates of methane are likely to change with the seasons (Titan's year is 29.5 Earth years) and evolve on a geological timescale (~10 5 Earth years) 2-4. Cassini observations suggest shoreline recession at a few south polar lakes during local summer 5 , but similar seasonal changes have yet to be observed at the north pole where lakes are larger and more numerous 6,7. We present three 'phantom lakes' that appear to be north polar surface liquids in winter observations by Cassini RADAR but that are inconsistent with lakes in infrared images obtained up to seven years later, after vernal equinox, suggesting that the liquids were removed in between. If this were the case, the phantom lakes could be interpreted as shallow ponds, with either a pure methane composition or a regolith porous enough to remove the less volatile ethane. These phantom lakes provide observational constraints on removal timescales for surface liquids at Titan's north pole. The location, size and longevity of surface liquid reservoirs affect sediment processing 7 , seasonal weather 8 , climate evolution 9 , and even, perhaps, their habitability 10. As solubility of the possible non-polar mixtures is generally low, short-lived lakes might be nutrient-poor 10 and thus have low astrobiological potential.
Fichier principal
Vignette du fichier
1085_5_merged_1544805758.pdf (11.91 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-02330630 , version 1 (13-11-2020)

Identifiants

Citer

Shannon Mackenzie, Jason Barnes, Jason Hofgartner, Samuel Birch, Matthew Hedman, et al.. The case for seasonal surface changes at Titan’s lake district. Nature Astronomy, 2019, 3 (6), pp.506-510. ⟨10.1038/s41550-018-0687-6⟩. ⟨hal-02330630⟩
136 Consultations
51 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More