D. Gobrecht
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View article: Condensation sequence of circumstellar cluster seeds (CSCCS)
Condensation sequence of circumstellar cluster seeds (CSCCS) Open
Introduction Traditionally, the condensation sequence of circumstellar dust is predicted based on the thermodynamic stabilities of specific condensates in the macroscopic bulk phase. However, at the (sub-) nanometer scale clusters with non…
View article: An accreting dwarf star orbiting the S-type giant star <i>π</i><sup>1</sup> Gru
An accreting dwarf star orbiting the S-type giant star <i>π</i><sup>1</sup> Gru Open
Context. At the end of their lives, low- to intermediate-mass stars reach the asymptotic giant branch (AGB), during which their photospheres expand by up to several hundred times and strong stellar winds develop. These changes lead to vari…
View article: The impact of third dredge-up on the mass loss of Mira variables
The impact of third dredge-up on the mass loss of Mira variables Open
Context: The details of the mass-loss process in the late stages of low- and intermediate-mass stellar evolution are not well understood, in particular its dependence on stellar parameters. Mira variables are highly suitable targets for st…
View article: The impact of third dredge-up on the mass loss of Mira variables
The impact of third dredge-up on the mass loss of Mira variables Open
Context. The details of the mass-loss process in the late stages of low- and intermediate-mass stellar evolution are not well understood, in particular its dependence on stellar parameters. Mira variables are highly suitable targets for st…
View article: Vanadium oxide clusters in substellar atmospheres
Vanadium oxide clusters in substellar atmospheres Open
Context . As a refractory material, vanadia (solid V 2 O 5 ) is likely to be found as a condensate in the atmospheres of substellar objects such as exoplanets and brown dwarfs. However, the nature of the nanometer-sized vanadium oxide clus…
View article: Vanadium oxide clusters in substellar atmospheres: A quantum chemical study
Vanadium oxide clusters in substellar atmospheres: A quantum chemical study Open
We aim to understand the formation of cloud condensation nuclei in oxygen-rich substellar atmospheres by calculating fundamental properties of the energetically most favorable vanadium oxide molecules and clusters. A hierarchical optimizat…
View article: ATOMIUM: Molecular inventory of 17 oxygen-rich evolved stars observed with ALMA
ATOMIUM: Molecular inventory of 17 oxygen-rich evolved stars observed with ALMA Open
Context. The dusty winds of cool evolved stars are a major contributor of the newly synthesised material enriching the Galaxy and future generations of stars. However, the details of the physics and chemistry behind dust formation and wind…
View article: Bottom-up dust nucleation theory in oxygen-rich evolved stars
Bottom-up dust nucleation theory in oxygen-rich evolved stars Open
Context. Spinel (MgAl 2 O 4 ) and krotite (CaAl 2 O 4 ) are alternative candidates to alumina (Al 2 O 3 ) as primary dust condensates in the atmospheres of oxygen-rich evolved stars. Moreover, spinel was proposed as a potential carrier of …
View article: Bottom-up dust nucleation theory in oxygen-rich evolved stars II. Magnesium and calcium aluminate clusters
Bottom-up dust nucleation theory in oxygen-rich evolved stars II. Magnesium and calcium aluminate clusters Open
Spinel (MgAl$_{2}$O$_{4}$) and krotite (CaAl$_{2}$O$_{4}$) are alternative candidates to alumina (Al$_2$O$_3$) as primary dust condensates in the atmospheres of oxygen-rich evolved stars. Moreover, spinel was proposed as a potential carrie…
View article: Infrared spectra of TiO<sub>2</sub> clusters for hot Jupiter atmospheres
Infrared spectra of TiO<sub>2</sub> clusters for hot Jupiter atmospheres Open
Context. Clouds appear to be an unavoidable phenomenon in cool and dense environments. Hence, their inclusion is a necessary part of explaining observations of exoplanet atmospheres, most recently those of WASP 96b with the James Webb Spac…
View article: Infrared spectra of TiO2 clusters for hot Jupiter atmospheres
Infrared spectra of TiO2 clusters for hot Jupiter atmospheres Open
Context. Clouds seem unavoidable in cool and dense environments, and hence, are necessary to explain observations of exoplanet atmospheres, most recently of WASP 96b with JWST. Understanding the formation of cloud condensation nuclei in no…
View article: Editorial: Cosmic dust—its formation, processing, and destruction
Editorial: Cosmic dust—its formation, processing, and destruction Open
EDITORIAL article Front. Astron. Space Sci., 24 July 2023Sec. Astrochemistry Volume 10 - 2023 | https://doi.org/10.3389/fspas.2023.1242545
View article: ATOMIUM: Probing the inner wind of evolved O-rich stars with new, highly excited H$_2$O and OH lines
ATOMIUM: Probing the inner wind of evolved O-rich stars with new, highly excited H$_2$O and OH lines Open
Water and the hydroxyl radical are major constituents of the envelope of O-rich late-type stars. Transitions involving energy levels that are highly excited have been observed in both H$_2$O and OH. These and more recently discovered trans…
View article: ATOMIUM: Probing the inner wind of evolved O-rich stars with new, highly excited H<sub>2</sub>O and OH lines
ATOMIUM: Probing the inner wind of evolved O-rich stars with new, highly excited H<sub>2</sub>O and OH lines Open
Context. Water (H 2 O) and the hydroxyl radical (OH) are major constituents of the envelope of O-rich late-type stars. Transitions involving energy levels that are rotationally or vibrationally highly excited (energies ≳4000 K) have been o…
View article: Chemical tracers of a highly eccentric binary orbit
Chemical tracers of a highly eccentric binary orbit Open
Binary interactions have been proposed to explain a variety of circumstellar structures seen around evolved stars, including asymptotic giant branch (AGB) stars and planetary nebulae. Studies resolving the circumstellar envelopes of AGB st…
View article: Mechanisms of SiO oxidation: Implications for dust formation
Mechanisms of SiO oxidation: Implications for dust formation Open
Reactions of SiO molecules have been postulated to initiate efficient formation of silicate dust particles in outflows around dying (AGB) stars. Both OH radicals and H 2 O molecules can be present in these environments and their reactions …
View article: The effect of thermal non-equilibrium on aerosol formation in astrophysical environments
The effect of thermal non-equilibrium on aerosol formation in astrophysical environments Open
From our Solar System, we know that gas giant planets are covered in clouds and we expect the same to hold true for many exoplanet gas giants. Knowing the composition and size of cloud particles and where they form within exoplanet atmosph…
View article: The effect of thermal non-equilibrium on kinetic nucleation
The effect of thermal non-equilibrium on kinetic nucleation Open
Context. Nucleation is considered to be the first step in dust and cloud formation in the atmospheres of asymptotic giant branch (AGB) stars, exoplanets, and brown dwarfs. In these environments dust and cloud particles grow to macroscopic …
View article: The effect of thermal non-equilibrium on kinetic nucleation
The effect of thermal non-equilibrium on kinetic nucleation Open
Nucleation is considered to be the first step in dust and cloud formation in the atmospheres of asymptotic giant branch (AGB) stars, exoplanets, and brown dwarfs. In these environments dust and cloud particles grow to macroscopic sizes whe…
View article: The VLT/SPHERE view of the ATOMIUM cool evolved star sample
The VLT/SPHERE view of the ATOMIUM cool evolved star sample Open
Context . Low- and intermediate-mass asymptotic giant stars and massive red supergiant stars are important contributors to the chemical enrichment of the Universe. They are among the most efficient dust factories of the Galaxy, harboring c…
View article: The VLT/SPHERE view of the ATOMIUM cool evolved star sample. I. Overview: Sample characterization through polarization analysis
The VLT/SPHERE view of the ATOMIUM cool evolved star sample. I. Overview: Sample characterization through polarization analysis Open
Aims. Through the ATOMIUM project, based on an ALMA large program, we aim to present a consistent view of a sample of 17 nearby cool evolved stars (Aymptotic Giant Branch and red supergiant stars). Methods. Here we present VLT/SPHERE-ZIMPO…
View article: Revisiting fundamental properties of TiO<sub>2</sub> nanoclusters as condensation seeds in astrophysical environments
Revisiting fundamental properties of TiO<sub>2</sub> nanoclusters as condensation seeds in astrophysical environments Open
Context. The formation of inorganic cloud particles takes place in several atmospheric environments, including those of warm, hot, rocky, and gaseous exoplanets, brown dwarfs, and asymptotic giant branch stars. The cloud particle formation…
View article: Experimental study of the removal of excited state phosphorus atoms by H2O and H2: implications for the formation of PO in stellar winds
Experimental study of the removal of excited state phosphorus atoms by H2O and H2: implications for the formation of PO in stellar winds Open
The reactions of the low-lying metastable states of atomic phosphorus, P(2D) and P(2P), with H2O and H2 were studied by the pulsed laser photolysis at 248 nm of PCl3, combined with laser-induced fluorescence detection of P(2D), P(2P), and …
View article: Dust in brown dwarfs and extra-solar planets -3D Monte Carlo versus kinetic approach of TiO2 seed formation
Dust in brown dwarfs and extra-solar planets -3D Monte Carlo versus kinetic approach of TiO2 seed formation Open
<p>Modelling the formation of cloud condensation nuclei is key for predicting cloud properties in and analyzing observational data from exoplanet and brown dwarf atmospheres. Based on kinetic results on cloud formation in exoplanets,…
View article: ATOMIUM: ALMA tracing the origins of molecules in dust forming oxygen rich M-type stars
ATOMIUM: ALMA tracing the origins of molecules in dust forming oxygen rich M-type stars Open
This overview paper presents ATOMIUM , a Large Programme in Cycle 6 with the Atacama Large Millimeter/submillimeter Array (ALMA). The goal of ATOMIUM is to understand the dynamics and the gas phase and dust formation chemistry in the winds…
View article: Bottom-up dust nucleation theory in oxygen-rich evolved stars
Bottom-up dust nucleation theory in oxygen-rich evolved stars Open
Context. Aluminium oxide (alumina; Al 2 O 3 ) is a promising candidate as a primary dust condensate in the atmospheres of oxygen-rich evolved stars. Therefore, alumina ‘seed’ particles might trigger the onset of stellar dust formation and …
View article: Bottom-up dust nucleation theory in oxygen-rich evolved stars I. Aluminium oxide clusters
Bottom-up dust nucleation theory in oxygen-rich evolved stars I. Aluminium oxide clusters Open
Aluminum oxide (alumina, Al$_{2}$O$_{3}$) is a promising candidate as a primary dust condensate in the atmospheres of oxygen-rich evolved stars. Therefore, alumina \textit{seed} particles might trigger the onset of stellar dust formation a…
View article: ATOMIUM: halide molecules around the S-type AGB star W Aquilae
ATOMIUM: halide molecules around the S-type AGB star W Aquilae Open
Context. S-type asymptotic giant branch (AGB) stars are thought to be intermediates in the evolution of oxygen- to carbon-rich AGB stars. The chemical compositions of their circumstellar envelopes are also intermediate but have not been st…
View article: ATOMIUM: Halide molecules around the S-type AGB star W Aquilae
ATOMIUM: Halide molecules around the S-type AGB star W Aquilae Open
S-type asymptotic giant branch (AGB) stars are thought to be intermediates in the evolution of oxygen- to carbon-rich AGB stars. The chemical compositions of their circumstellar envelopes are also intermediate, but have not been studied in…