相关论文: A comparison of chemistry and dust cloud formation…

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…

Based on a simple thermodynamical argument, we proposed a unified cloudy model (UCM) with a warm dust cloud deep in the photosphere. We showed, for the first time, that a single grid of model photospheres (Teff between 800 and 2600K) offers…

Understanding of cloud microphysics and the evolution of cloud structures in sub-stellar atmospheres remains a key challenge in the JWST era. The abundance of new JWST data necessitates models that are suitable for coupling with large-scale…

We aim to understand the correlation between cloud formation and alkali line formation in substellar atmospheres.We perform line profile calculations for Na I and K I based on the coupling of our kinetic model for the formation and…

M-dwarfs are emerging in the literature as promising targets for detecting low-mass, Earth-like planets. An important step in this process is to determine the stellar parameters of the M-dwarf host star as accurately as possible. Different…

A sophisticated approach to condensate opacity is required to properly model the atmospheres of L and T dwarfs. Here we review different models for the treatment of condensates in brown dwarf atmospheres. We conclude that models which…

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…

State-of-the-art JWST observations are unveiling unprecedented views into the atmospheres of substellar objects in the infrared, further highlighting the importance of clouds. Current forward models struggle to fit the silicate clouds…

We aim to understand cloud formation in substellar objects. We combined the non-equilibrium, stationary cloud model of Helling, Woitke & Thi (2008; seed formation, growth, evaporation, gravitational settling, element conservation) with the…

The large scale structure of a brown dwarf atmosphere is determined by an interplay of convection, radiation, dust formation, and gravitational settling, which possibly provides an explanation for the observed variability. The result is an…

The reliability of modeling the far-IR continuum to 13CO J=1-0 spectral line ratios applied to the Orion clouds (Wall 2006) is tested by applying the models to simulated data. The two-component models are found to give the dust-gas…

The precipitation of cloud particles in brown dwarf and exoplanet atmospheres establishes an ongoing downward flux of condensable elements. To understand the efficiency of cloud formation, it is therefore crucial to quantify the…

Brown dwarfs -- substellar bodies more massive than planets but not massive enough to initiate the sustained hydrogen fusion that powers self-luminous stars -- are born hot and slowly cool as they age. As they cool below about 2,300 K,…

We present the first results from applying the spectral inversion technique in the cloudy L dwarf regime. Our new framework provides a flexible approach to modelling cloud opacity which can be built incrementally as the data requires, and…

Warm Saturn type exoplanets orbiting M-dwarfs are particularly suitable for in-depth cloud characterisation through transmission spectroscopy due to their favourable stellar to planetary radius contrast. However, modelling cloud formation…

As comets journey into the inner solar system, they deliver particulates and volatile gases into their comae that reveal the most primitive materials in the solar system. Cometary dust particles provide crucial information for assessing the…

Mixed-phase clouds, composed of supercooled liquid droplets and ice crystals, play a critical role in weather and climate systems. Their complex microphysical interactions and coupling with turbulence at microscales govern the cloud…

Recent observations revealed that the infrared colors of L and T dwarfs show a large variation at a given T_ eff and this result may imply that the thickness of the dust cloud is changing at a given T_ eff. Our Unified Cloudy Model (UCM),…

We aim at understanding the formation of cloud layers in quasi-static substellar atmospheres. The time-dependent description presented in (Helling & Woitke 2006) is a kinetic model describing nucleation, growth and evaporation. It is…

We examine several different simplified approaches for modelling the chemistry of CO in three-dimensional numerical simulations of turbulent molecular clouds. We compare the different models both by looking at the behaviour of integrated…