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Related papers: Cloud formation in substellar atmospheres

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Brown dwarfs are massive, giant exoplanet analogues subject to variability and colour changes, known as the L/T transition, fundamental for their thermal evolution. The drivers of the L/T transition remain elusive, with atmospheric…

Earth and Planetary Astrophysics · Physics 2025-10-22 Lucas Teinturier , Benjamin Charnay , Aymeric Spiga , Bruno Bezard

We review the current state of observational work on the formation of brown dwarfs, focusing on their initial mass function, velocity and spatial distributions at birth, multiplicity, accretion, and circumstellar disks. The available…

Numerous observational evidence has suggested the presence of active meteorology in the atmospheres of brown dwarfs. A near-infrared brightness variability has been observed. Clouds have a major role in shaping the thermal structure and…

Earth and Planetary Astrophysics · Physics 2022-05-04 Maxence Lefèvre , Xianyu Tan , Elspeth K. H. Lee , R. T. Pierrehumbert

Brown dwarfs and giant gas extrasolar planets have cold atmospheres with a rich chemical compositions from which mineral cloud particles form. Their properties, like particle sizes and material composition, vary with height, and the mineral…

Earth and Planetary Astrophysics · Physics 2016-06-22 Ch. Helling , P. B. Rimmer , I. M. Rodriguez-Barrera , Kenneth Wood , G. B. Robertson , C. R. Stark

Electric discharges were detected directly in the cloudy atmospheres of Earth, Jupiter and Saturn, are debatable for Venus, and indirectly inferred for Neptune and Uranus in our solar system. Sprites (and other types of transient luminous…

Earth and Planetary Astrophysics · Physics 2015-06-12 Ch. Helling , M. Jardine , C. Stark , D. Diver

Brown dwarfs bridge the gap between the stellar and planetary mass regimes. Evolving from conditions very similar to the lowest-mass stars, the atmospheres of older brown dwarfs closely resemble those expected in close-in extrasolar giant…

Clouds and hazes are important throughout our solar system and in the atmospheres of brown dwarfs and extrasolar giant planets. Among the brown dwarfs, clouds control the colors and spectra of the L-dwarfs; the disappearance of clouds helps…

Astrophysics · Physics 2007-05-23 M. S. Marley , A. S. Ackerman

Transmission spectrum surveys have suggested the ubiquity of high-altitude clouds in exoplanetary atmospheres. Theoretical studies have investigated the formation processes of the high-altitude clouds; however, cloud particles have been…

Earth and Planetary Astrophysics · Physics 2020-03-18 Kazumasa Ohno , Satoshi Okuzumi , Ryo Tazaki

Clouds of metal-bearing condensates play a critical role in shaping the emergent spectral energy distributions of the coolest classes of low-mass stars and brown dwarfs, L and T dwarfs. Because condensate clouds in planetary atmospheres…

Extrasolar planets appear in a chemical diversity unseen in our own solar system. Despite their atmospheres being cold, continuous and transient plasma processes do affect these atmosphere where clouds form with great efficiency. Clouds can…

Solar and Stellar Astrophysics · Physics 2018-09-26 Ch. Helling , I. Vorgul

Dust formation in brown dwarf atmospheres is studied by utilising a model for driven turbulence in the mesoscopic scale regime. We apply a pseudo-spectral method where waves are created and superimposed within a limited wavenumber interval.…

Astrophysics · Physics 2007-05-23 Ch. Helling , R. Klein , P. Woitke , U. Nowak , E. Sedlmayr

Brown dwarfs are commonly regarded as easily-observed templates for exoplanet studies, with comparable masses, physical sizes and atmospheric properties. There is indeed considerable overlap in the photospheric temperatures of the coldest…

Solar and Stellar Astrophysics · Physics 2009-03-10 Adam J. Burgasser

Clouds form in atmospheres of brown dwarfs and planets. The cloud particle formation processes are similar to the dust formation process studied in circumstellar shells of AGB stars and in Supernovae. Cloud formation modelling in substellar…

Solar and Stellar Astrophysics · Physics 2021-06-04 E. K. H. Lee , Ch. Helling , H. Giles , S. T. Bromley

We calculate the formation of dust clouds in atmospheres of giant gas-planets. The chemical structure and the evolution of the grain size distribution in the dust cloud layer is discussed based on a consistent treatment of seed formation,…

Astrophysics · Physics 2007-11-26 Christiane Helling

The observational properties of brown dwarfs pose challenges to the theory of star formation. Because their mass is much smaller than the typical Jeans mass of interstellar clouds, brown dwarfs are most likely formed through secondary…

Astrophysics · Physics 2007-05-23 Ing-Guey Jiang , G. Laughlin , D. N. C. Lin

Brown dwarfs and exoplanets provide unique atmospheric regimes that hold information about their formation routes and evolutionary states. Modelling mineral cloud particle formation is key to prepare for missions and instruments like…

Earth and Planetary Astrophysics · Physics 2022-07-13 Dominic Samra , Christiane Helling , Tilman Birnstiel

We present a new suite of atmosphere models with flexible cloud parameters to investigate the effects of clouds on brown dwarfs across the L/T transition. We fit these models to a sample of 13 objects with well-known masses, distances, and…

Solar and Stellar Astrophysics · Physics 2021-06-21 Laci Shea Brock , Travis Barman , Quinn M. Konopacky , Jordan M. Stone

Context. Observations suggest that exoplanets such as HD 189733b form clouds in their atmospheres which have a strong feedback onto their thermodynamical and chemical structure, and overall appearance. Aims. Inspired by mineral cloud…

Earth and Planetary Astrophysics · Physics 2021-06-04 E. K. H. Lee , Ch. Helling , I. Dobbs-Dixon , D. Juncher

Clouds form in the atmospheres of planets where they can determine the observable spectra, the albedo and phase curves. Cloud properties are determined by the local thermodynamical and chemical conditions of an atmospheric gas. A retrieval…

Earth and Planetary Astrophysics · Physics 2017-09-20 G. Mahapatra , Ch. Helling , Y. Miguel

As brown dwarfs cool, a variety of species condense in their atmospheres, forming clouds. Iron and silicate clouds shape the emergent spectra of L dwarfs, but these clouds dissipate at the L/T transition. A variety of other condensates are…

Solar and Stellar Astrophysics · Physics 2015-06-05 Caroline V. Morley , Jonathan J. Fortney , Mark S. Marley , Channon Visscher , Didier Saumon , S. K. Leggett