Dust in brown dwarfs and extrasolar planets - V. Cloud formation in carbon- and oxygen-rich environments
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In this article, a system of dust moment equations and element conservation for a prescribed Drift-Phoenixatmosphere structure is proposed to model cloud formation processes for carbon-rich exoplanetary atmospheres.Abstract:
Context. Recent observations indicate potentially carbon-rich (C/O > 1) exoplanet atmospheres. Spectral fitting methods for brown dwarfs and exoplanets have invoked the C/O ratio as additional parameter but carbon-rich cloud formation modeling is a challenge for the models applied. The determination of the habitable zone for exoplanets requires the treatment of cloud formation in chemically different regimes. Aims. We aim to model cloud formation processes for carbon-rich exoplanetary atmospheres. Disk models show that carbon-rich or near-carbon-rich niches may emerge and cool carbon planets may trace these particular stages of planetary evolution.Methods. We extended our kinetic cloud formation model by including carbon seed formation and the formation of C[s], TiC[s], SiC[s], KCl[s], and MgS[s] by gas-surface reactions. We solved a system of dust moment equations and element conservation for a prescribed Drift-Phoenixatmosphere structure to study how a cloud structure would change with changing initial C/O0 = 0.43... 10.0.Results. The seed formation efficiency is lower in carbon-rich atmospheres than in oxygen-rich gases because carbon is a very effective growth species. The consequence is that fewer particles make up a cloud if C/O0 > 1. The cloud particles are smaller in size than in an oxygen-rich atmosphere. An increasing initial C/O ratio does not revert this trend because a much greater abundance of condensible gas species exists in a carbon-rich environment. Cloud particles are generally made of a mix of materials: carbon dominates if C/O0 > 1 and silicates dominate if C/O0 = 3.0 or 10.0.Conclusions. Carbon-rich atmospheres form clouds that are made of particles of height-dependent mixed compositions, sizes and numbers. The remaining gas phase is far less depleted than in an oxygen-rich atmosphere. Typical tracer molecules are HCN and C2 H2 in combination with a featureless, smooth continuum due to a carbonaceous cloud cover, unless the cloud particles become crystalline.read more
Citations
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Journal ArticleDOI
Equilibrium chemistry down to 100 K - Impact of silicates and phyllosilicates on carbon/oxygen ratio
Peter Woitke,Christiane Helling,G. H. Hunter,J. D. Millard,G. E. Turner,M. Worters,Jasmina Blecic,J. W. Stock +7 more
TL;DR: In this paper, the authors introduce a fast and versatile computer code, GGchem, to determine the chemical composition of gases in thermo-chemical equilibrium down to 100 K, with or without equilibrium condensation.
Journal ArticleDOI
Equilibrium chemistry down to 100 K. Impact of silicates and phyllosilicates on the carbon to oxygen ratio
Peter Woitke,Christiane Helling,Christiane Helling,G. H. Hunter,J. D. Millard,G. E. Turner,M. Worters,Jasmina Blecic,J. W. Stock +8 more
TL;DR: In this paper, a fast and versatile computer code, GGCHEM, was introduced to determine the chemical composition of gases in thermo-chemical equilibrium down to 100 K, with or without equilibrium condensation.
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References
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Journal ArticleDOI
A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion
David K. Sing,Jonathan J. Fortney,Nikolay Nikolov,Hannah R. Wakeford,Tiffany Kataria,Thomas M. Evans,Suzanne Aigrain,Gilda E. Ballester,Adam Burrows,Drake Deming,Jean-Michel Desert,Neale P. Gibson,Gregory W. Henry,Catherine M. Huitson,Heather Knutson,Alain Lecavelier des Etangs,Frederic Pont,Adam P. Showman,Alfred Vidal-Madjar,Michael H. Williamson,Paul Wilson +20 more
TL;DR: The difference between the planetary radius measured at optical and infrared wavelengths is an effective metric for distinguishing different atmosphere types, so that strong water absorption lines are seen in clear-atmosphere planets and the weakest features are associated with clouds and hazes.
Journal ArticleDOI
Neglected Clouds in T and Y Dwarf Atmospheres
Caroline V. Morley,Jonathan J. Fortney,Mark S. Marley,Channon Visscher,Didier Saumon,S. K. Leggett +5 more
TL;DR: In this paper, a suite of models between Teff = 400 and 1300 K, log g = 4.0 and 5.5, and condensate sedimentation efficiencies fro m fsed = 2 to 5.
Journal ArticleDOI
Radiation thermo-chemical models of protoplanetary disks I. Hydrostatic disk structure and inner rim
TL;DR: In this article, a new disk code called ProDiMo is proposed for interpreting far IR gas emission lines, such as will be observed by the Herschel observatory, related to the Gasps open time key program.
Journal ArticleDOI
Stabilizing Cloud Feedback Dramatically Expands the Habitable Zone of Tidally Locked Planets
TL;DR: In this paper, the authors used global climate models with sophisticated cloud schemes to show that due to a stabilizing cloud feedback, tidally locked planets can be habitable at twice the stellar flux found by previous studies.
Journal ArticleDOI
A high C/O ratio and weak thermal inversion in the atmosphere of exoplanet WASP-12b
Nikku Madhusudhan,Nikku Madhusudhan,Joseph Harrington,Kevin B. Stevenson,Sarah Nymeyer,Christopher J. Campo,Peter J. Wheatley,Drake Deming,Jasmina Blecic,Ryan A. Hardy,Nate B. Lust,David R. Anderson,Andrew Collier-Cameron,Christopher B. T. Britt,William C. Bowman,Leslie Hebb,Coel Hellier,Pierre F. L. Maxted,Don Pollacco,Richard G. West +19 more
TL;DR: It is found that the extremely irradiated atmosphere of WASP-12b lacks a prominent thermal inversion (or stratosphere) and has very efficient day–night energy circulation, in stark contrast to theoretical predictions for the most highly irradiated hot-Jupiter atmospheres.
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