The need for small-scale turbulence in atmospheres of substellar objects

Christiane Helling

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Brown dwarfs and giant gas planets are substellar objects whose spectral appearance is determined by the chemical composition of the gas and the solids/liquids in the atmosphere. Atmospheres of substellar objects possess two major scale regimes: large-scale convective motions + gravitational settling and small-scale turbulence + dust formation. Turbulence initiates dust formation spot-like on small scale, while the dust feeds back into the turbulent fluid field by its strong radiative cooling. Small, imploding dust containing areas result which eventually become isothermal. Multi-dimensional simulations show that these small-scale dust structures gather into large-scale structures, suggesting the formation of clouds made of dirty dust grains. The chemical composition of the grains, and thereby the chemical evolution of the gas phase, is a function of temperature and depends on the grain's history.
Original languageEnglish
Title of host publicationProceedings of the Workshop on "Interdisciplinary Aspects of Turbulence" Ringberg Castle, Tegernsee, Germany, April 18 - 22, 2005
EditorsF. Kupka, W. Hillebrandt
Place of PublicationGarching
PublisherMax-Planck-Institut für Astrophysik
Number of pages7
Publication statusPublished - 9 Jun 2005
EventTalk at Ringberg workshop on "Interdisciplinary Aspects of Turbulence" - Rinberg Castle, Tegernsee, Germany
Duration: 18 Apr 200522 Apr 2005


WorkshopTalk at Ringberg workshop on "Interdisciplinary Aspects of Turbulence"


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