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Most brown dwarfs have atmospheres with temperatures cold enough to form clouds. A variety of materials likely condense, including refractory metal oxides and silicates; the precise compositions and crystal structures of predicted cloud…

Solar and Stellar Astrophysics · Physics 2021-11-03 Jessica L. Luna , Caroline V. Morley

Stably-stratified layers may be present at the top of the electrically-conducting fluid layers of many planets either because the temperature gradient is locally subadiabatic or because a stable composition gradient is maintained by the…

Earth and Planetary Astrophysics · Physics 2022-11-08 Celine Guervilly

The intense irradiation received by hot Jupiters suppresses convection in the outer layers of their atmospheres and lowers their cooling rates. "Inflated" hot Jupiters, i.e., those with anomalously large transit radii, require additional…

Earth and Planetary Astrophysics · Physics 2015-05-19 Andrew N. Youdin , Jonathan L. Mitchell

Context. Classical chemically peculiar stars exhibit atmospheres that are often structured by the effects of atomic diffusion. As a result of these elemental diffusion and horizontal abundance variations, photospheric temperature varies at…

Solar and Stellar Astrophysics · Physics 2025-02-19 A. ud-Doula , J. Krticka , B. Kubátová

The observed rapid onset of star formation in molecular clouds requires rapid formation of dense fragments which can collapse individually before being overtaken by global gravitationally-driven flows. Many previous investigations have…

Astrophysics · Physics 2009-11-13 F. Heitsch , L. Hartmann , A. Burkert , ;

We study the oscillations of relativistic stars, incorporating key physics associated with internal composition, thermal gradients and crust elasticity. Our aim is to develop a formalism which is able to account for the state-of-the-art…

General Relativity and Quantum Cosmology · Physics 2015-09-16 C. J. Krüger , W. C. G. Ho , N. Andersson

Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASSJ22282889-431026 over the…

Water vapour atmospheres with content equivalent to the Earth's oceans, resulting from impacts or a high insolation, were found to yield a surface magma ocean. This was, however, a consequence of assuming a fully convective structure. Here…

Earth and Planetary Astrophysics · Physics 2023-11-22 Franck Selsis , Jérémy Leconte , Martin Turbet , Guillaume Chaverot , Émeline Bolmont

Thermal emission spectra of hot Jupiters have led to key constraints on thermal inversions (or 'stratospheres') in their atmospheres with important implications for their atmospheric processes. Canonically, thermal inversions in hot…

Earth and Planetary Astrophysics · Physics 2019-03-29 Siddharth Gandhi , Nikku Madhusudhan

Brown dwarfs are essential targets for understanding planetary and sub-stellar atmospheres across a wide range of thermal and chemical conditions. As surveys continue to probe ever deeper, and as observing capabilities continue to improve,…

Earth and Planetary Astrophysics · Physics 2021-11-24 Shih-Yun Tang , Tyler D. Robinson , Mark S. Marley , Natasha E. Batalha , Roxana Lupu , L. Prato

Stars form within molecular clouds but our understanding of this fundamental process remains hampered by the complexity of the physics that drives their evolution. We review our observational and theoretical knowledge of molecular clouds…

Astrophysics of Galaxies · Physics 2015-06-12 Patrick Hennebelle , Edith Falgarone

White dwarfs are compact objects with atmospheres containing mainly light elements, hydrogen or helium. Because of their surface high gravitational field, heavy elements diffuse downwards in a very short timescale compared to the…

Solar and Stellar Astrophysics · Physics 2022-04-06 F. C. Wachlin , G. Vauclair , S. Vauclair

We examine the thermal evolution of a sequence of compact objects containing low-mass hadronic and high-mass quark-hadronic stars constructed from a microscopically motivated equation of state. The dependence of the cooling tracks in the…

High Energy Astrophysical Phenomena · Physics 2011-10-19 Daniel Hess , Armen Sedrakian

Thermal convection stands out as an exceptionally efficient thermal transport mechanism, distinctly separate from conduction and radiation. Yet, the inherently elusive nature of fluid motion poses challenges in accurately controlling…

Applied Physics · Physics 2023-09-26 Peng Jin , Gaole Dai , Fubao Yang

The transition between the two lowest-luminosity spectral classes of brown dwarfs--the L dwarfs and T dwarfs--is traversed by nearly all brown dwarfs as they cool over time. Yet distinct features of this transition, such as the "J-band…

Astrophysics · Physics 2009-11-13 Adam J. Burgasser

We present a Monte Carlo simulation designed to predict the vertical velocity dispersion of brown dwarfs in the Milky Way. We show that since these stars are constantly cooling, the velocity dispersion has a noticeable trend with spectral…

Just as correlations between fluctuating radial and azimuthal velocities produce a coherent stress contributing to the angular momentum transport in turbulent accretion disks, correlations in the velocity and temperature fluctuations…

Astrophysics · Physics 2009-11-07 Steven A. Balbus

Heat conduction in a random packing of hard spheres is studied by nonequilibrium molecular dynamics simulation. We find a hard-sphere random packing shows higher thermal conductivity than a crystalline packing with same packing fraction.…

Statistical Mechanics · Physics 2010-12-15 Shigenori Matsumoto , Tomoaki Nogawa , Takashi Shimada , Nobuyasu Ito

We developed a simple, physical and self-consistent cloud model for brown dwarfs and young giant exoplanets. We compared different parametrisations for the cloud particle size, by either fixing particle radii, or fixing the mixing…

Earth and Planetary Astrophysics · Physics 2018-03-14 Benjamin Charnay , Bruno Bézard , Jean-Loup Baudino , Mickaël Bonnefoy , Anthony Boccaletti , Raphaël Galicher

Fingering convection (also known as thermohaline convection) is a process that drives the vertical transport of chemical elements in regions of stellar radiative zones where the mean molecular weight increases with radius. Recently,…

Solar and Stellar Astrophysics · Physics 2024-02-07 Adrian E. Fraser , Sam A. Reifenstein , Pascale Garaud