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Brown dwarfs form mineral clouds in their atmospheres, where charged particles can produce large-scale discharges in form of lightning resulting in a substantial sudden increase of local ionisation. Brown dwarfs are observed to emit…

Solar and Stellar Astrophysics · Physics 2016-01-28 Irena Vorgul , Christiane Helling

We consider a generic system operating under non-equilibrium conditions. Explicitly, we consider an inertial classical Brownian particle dwelling a periodic structure with a spatially broken reflection symmetry. The particle is coupled to a…

Statistical Mechanics · Physics 2020-07-15 P. Hänggi , J. Łuczka , J. Spiechowicz

This work aims to improve the current understanding of the atmospheres of brown dwarfs, especially cold ones with spectral type T and Y, whose modeling is a current challenge. Silicate and iron clouds are believed to disappear at the…

Solar and Stellar Astrophysics · Physics 2015-06-24 P. Tremblin , D. S. Amundsen , P. Mourier , I. Baraffe , G. Chabrier , B. Drummond , D. Homeier , O. Venot

We consider the dynamical evolution of an interstellar cloud that is initially in thermal equilibrium in the warm phase and is then subjected to a sudden increase in the pressure of its surroundings. We find that if the initial plasma beta…

Astrophysics · Physics 2009-11-13 A. J. Lim , S. A. E. G. Falle , T. W. Hartquist

We present a new set of solar metallicity atmosphere and evolutionary models for very cool brown dwarfs and self-luminous giant exoplanets, which we term ATMO 2020. Atmosphere models are generated with our state-of-the-art 1D…

We study the effects of clouds on the dynamical and chemical evolution of gas-rich dwarf galaxies, in particular focusing on two model galaxies similar to IZw18 and NGC1569. We consider both scenarios, clouds put at the beginning of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 S. Recchi , G. Hensler

Supersonic turbulence is a large reservoir of suprathermal energy in the interstellar medium. Its dissipation, because it is intermittent in space and time, can deeply modify the chemistry of the gas. We further explore a hybrid method to…

Astrophysics of Galaxies · Physics 2009-11-13 Benjamin Godard , Edith Falgarone , Guillaume Pineau Des Forêts

We report new infrared spectroscopic observations of cool DQ white dwarfs by using Coolspec on the 2.7m Harlan-Smith Telescope. DQs have helium-rich atmospheres with traces of molecular carbon thought to be the result of convective…

Astrophysics · Physics 2007-05-23 M. Kilic , D. E. Winget , T. von Hippel , D. F. Lester , D. Saumon

Much of what we know about molecular clouds, and by extension star formation, comes from molecular line observations. Interpreting these correctly requires knowledge of the underlying molecular abundances. Simulations of molecular clouds…

Astrophysics of Galaxies · Physics 2023-08-02 F. D. Priestley , P. C. Clark , S. C. O. Glover , S. E. Ragan , O. Fehér , L. R. Prole , R. S. Klessen

Close-in warm Jupiters orbiting M dwarf stars are expected to exhibit diverse atmospheric chemistry, with clouds playing a key role in shaping their albedo, heat distribution, and spectral properties. We study WASP-80b, a warm Jupiter…

Thermal history models, that have been used to understand the geological history of Earth, are now being coupled to climate models to map conditions that allow planets to maintain surface water over geologic time - a criteria considered…

Earth and Planetary Astrophysics · Physics 2020-01-08 Johnny Seales , Adrian Lenardic , William Moore

Using computer simulations, we explored gaseous infall as a possible explanation for the starburst phase in Blue Compact Dwarf galaxies. We simulate a cloud impact by merging a spherical gas cloud into an isolated dwarf galaxy. We…

Astrophysics of Galaxies · Physics 2015-06-19 Robbert Verbeke , Sven De Rijcke , Mina Koleva , Annelies Cloet-Osselaer , Bert Vandenbroucke , Joeri Schroyen

We present results from the first hydrodynamical star formation calculation to demonstrate that brown dwarfs are a natural and frequent product of the collapse and fragmentation of a turbulent molecular cloud. The brown dwarfs form via the…

Astrophysics · Physics 2009-11-07 Matthew R. Bate , Ian A. Bonnell , Volker Bromm

Ultra-cool dwarfs of the L spectral type (Teff=1400-2200K) are known to have dusty atmospheres. Asymmetries of the dwarf surface may arise from rotationally-induced flattening and dust-cloud coverage, and may result in non-zero linear…

Solar and Stellar Astrophysics · Physics 2015-05-13 B. Goldman , J. Pitann , M. R. Zapatero Osorio , C. A. L. Bailer-Jones , V. J. S. Bejar , J. A. Caballero , Th. Henning

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…

Over the past decade considerable effort, both observational and theoretical, has been directed towards a more accurate determination of the stellar lower main sequence and of the sub-stellar domain covered by Brown Dwarfs and Planets. A…

Astrophysics · Physics 2009-09-25 Isabelle Baraffe , France Allard

A modification of the classical primitive equations of the atmosphere is considered in order to take into account important phase transition phenomena due to air saturation and condensation. We provide a mathematical formulation of the…

Analysis of PDEs · Mathematics 2015-06-19 Michele Coti Zelati , Aimin Huang , Igor Kukavica , Roger Temam , Mohammed Ziane

The L/T transition is an important evolutionary phase in brown dwarf atmospheres, providing us with a unique opportunity to explore the effects of clouds, convection, winds, gravity and metallicity across a very narrow temperature range.…

Nonequilibrium thermodynamics formalism is proposed to derive the flux of grainy (bubbles-containing) matter, emerging in a nucleation growth process. Some power and non-power limits, due to the applied potential as well as owing to basic…

Soft Condensed Matter · Physics 2009-11-10 J. M. Rubi , A. Gadomski

Brown dwarfs are compact objects that do not reach temperatures high enough to produce sustained hydrogen fusion. Consequently, they cool over time, gradually evolving through later spectral types. In fact, three new spectral types (L, T,…

Solar and Stellar Astrophysics · Physics 2026-05-20 A. R. Callen , I. H. Bustos Fierro , M. Gómez