226 citations · 400 across the 4 of their papers we have counts for
5 papers
A comparison of chemistry and dust cloud formation in ultracool dwarf model atmospheres
Ch. Helling, A. Ackerman, F. Allard +8
The atmospheres of substellar objects contain clouds of oxides, iron, silicates, and other refractory condensates. Water clouds are expected in the coolest objects. The opacity of…
Consistent simulations of substellar atmospheres and non-equilibrium dust-cloud formation
Christiane Helling, Matthias Dehn, Peter Woitke +1
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, evaporat…
The Influence of Dust Formation Modelling on Na I and K I Line Profiles in Substellar Atmospheres
C. M. S. Johnas, Ch. Helling, M. Dehn +2
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…
Comparison of cloud models for Brown Dwarfs
Ch. Helling, A. Ackerman, F. Allard +8
A test case comparison is presented for different dust cloud model approaches applied in brown dwarfs and giant gas planets. We aim to achieve more transparency in evaluating the u…
Abundances In Very Metal Poor Dwarf Stars
Judith G. Cohen, Norbert Christlieb, Andrew McWilliam +7
We discuss the detailed composition of 28 extremely metal-poor dwarfs, 22 of which are from the Hamburg/ESO Survey, based on Keck Echelle spectra. Our sample has a median [Fe/H] of…