H. Mutschke

Friedrich Schiller University Jena

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

C. Jäger

Friedrich Schiller University Jena

J. Dorschner

Friedrich Schiller University Jena

Th. Henning

Max Planck Institute for Astronomy

Thomas Henning

Max Planck Institute for Astronomy

Th. Posch

University of Vienna

Akemi Tamanai

Pioneer (Japan)

Anja C. Andersen

University of Copenhagen

B. Begemann

Max Planck Society

D. Fabian

International Society for Optics and Photonics

F. Huisken

Friedrich Schiller University Jena

Cooperative Institutions

Friedrich Schiller University Jena

Max Planck Institute for Astronomy

Max Planck Society

Centre National de la Recherche Scientifique

SRON Netherlands Institute for Space Research

Helmholtz Institute Jena

European Space Research and Technology Centre

Heidelberg University

European Space Astronomy Centre

University of Amsterdam

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Effects of anisotropy on absorption cross-section spectra of medium-sized spheroidal corundum particles

Astronomy and Astrophysics (2021)

Sonja Höfer H. Mutschke Th.G. Mayerhöfer

Context. It has been widely accepted that corundum particles condense in the atmospheres of oxygen-rich asymptotic giant branch stars and effectively produce an infrared emission feature at 13 μ m. Laboratory experiments have predicted that these particles have the shape of oblate spheroids. Aims. We investigate the influence of the material anisotropy of uniaxial corundum on absorption cross section spectra of medium sized spheroidal particles in the infrared spectral region. Methods. We compared absorption cross-section spectra of the anisotropic corundum particles gained by finite-difference time-domain simulations to spectra calculated by a weighted sum approximation of the according fictive isotropic materials, with one material having the dielectric function of the a – b -plane and the other having the dielectric function of the c -axis of corundum. We carried out investigations for different axes ratios of the spheroids, particles volumes, and different geometries of the dielectric axes to the particle axes as well as to the polarization and propagation direction of the incident light. Results. We observed several effects attributed to anisotropy that are non-additive, so that they cannot be reproduced with the combined spectra of the isotropic materials. Conclusions. Care should be taken when calculating the corundum infrared spectrum with simpler approaches. When particle sizes above 1 μ m are to be considered, the T-matrix formalism delivers correct band shifts and bulk modes for many, but not all bands. This remains true in orientation-averaged spectra and for particles in the 0.1 μ m size range.

Corundum

Absorption cross section

10.1051/0004-6361/202038931

Cite

Citations (6)

MOP: A Space Debris and Interplanetary Dust Sample Return Mission

K. Scherer M. Hilchenbach E. Kirsch S. Livi J. Bendisch

Interplanetary space

Sample (material)

Cite

Citations (0)

Dust absorption and scattering in the silicon K-edge

Astronomy and Astrophysics (2019)

S. T. Zeegers E. Costantini Daniele Rogantini C. P. de Vries H. Mutschke

The composition and properties of interstellar silicate dust are not well understood. In X-rays, interstellar dust can be studied in detail by making use of the fine structure features in the Si K-edge. The features in the Si K-edge offer a range of possibilities to study silicon-bearing dust, such as investigating the crystallinity, abundance, and the chemical composition along a given line of sight. We present newly acquired laboratory measurements of the silicon K-edge of several silicate-compounds that complement our measurements from our earlier pilot study. The resulting dust extinction profiles serve as templates for the interstellar extinction that we observe. The extinction profiles were used to model the interstellar dust in the dense environments of the Galaxy. The laboratory measurements, taken at the Soleil synchrotron facility in Paris, were adapted for astrophysical data analysis and implemented in the SPEX spectral fitting program. The models were used to fit the spectra of nine low-mass X-ray binaries located in the Galactic center neighborhood in order to determine the dust properties along those lines of sight. Most lines of sight can be fit well by amorphous olivine. We also established upper limits on the amount of crystalline material that the modeling allows. We obtained values of the total silicon abundance, silicon dust abundance, and depletion along each of the sightlines. We find a possible gradient of $0.06\pm0.02$ dex/kpc for the total silicon abundance versus the Galactocentric distance. We do not find a relation between the depletion and the extinction along the line of sight.

Extinction (optical mineralogy)

Silicon monoxide

10.1051/0004-6361/201935050

Cite

Citations (33)

The X-ray side of the absorption by interstellar dust in the Milky Way

E. Costantini Cor de Vries S. T. Zeegers Frank M. F. de Groot H. Mutschke

10.22323/1.207.0006

Cite

Citations (3)

Transient dust in warm debris disks Detection of Fe-rich olivine grains (Corrigendum)

J. Olofsson Á. Juhász H. Mutschke Akemi Tamanai A. Moór

−3.2 0 + 0.7 12.9 ± 1.4 HD 69830 16.8 ± 3.7 20.0 ± 0.9 0 + 0.7 1.9 +9.0 −1.9 20.9 ± 5.1 4.6 ± 0.7 8.1 ± 1.9 7.0 ± 4.2 20.8 ± 4.1 BD+20 307 48.2 ± 1.0 10.5 ± 0.9 0 + 0.7 8.7 ± 0.7 14.0 ± 1.6 2.7 ± 1.0 15.9 ± 0.7 0 + 0.7 0 + 0.7 HD 15407 A 0 + 0.7 13.5 ± 5.8 14.7 ± 5.0 0 + 0.7 0 + 0.7 0 + 0.9 0 + 0.8 51.9 ± 1.6 19.8 ± 10.2 HD 169666 0 + 0.8 0 + 0.7 0 + 0.7 35.8 ± 0.9 0 + 0.9 20.0 ± 7.9 22.2 ± 0.9 10.3 ± 0.7 11.6 ± 4.6 HD 98800 B 15.3 ± 0.7 43.0 ± 0.7 0 + 0.7 7.4 ± 1.2 0 + 0.8 0.8 ± 0.7 15.7 ± 5.2 0 + 0.7 17.8 ± 5.3 ID 8 27.8 ± 8.2 0 + 0.7 0 + 0.7 51.2 ± 11.7 7.5 ± 2.7 1.7 +1.8 −1.7 0 + 0.7 0 + 0.7 11.8 ± 2.0 is propagated only to the relative abundances. We used smax of 1 μm and 1 mm for crystalline and amorphous grains, respectively. Therefore, Δlogs (and thusn) being smaller for crystalline species, their relative abundances increase with respect to amorphous grains. The trends between different crystalline (or amorphous) grains however remain the same (e.g., Fe-rich versus Mgrich crystalline olivine grains), since they have the same Δlogs. Consequently, the best fit parameters remain the same, as well as the best fit models, only the final relative abundances of the dust species required to fit the observed spectrum are modified. Table 1 shows the correct abundances as well as the newly estimated uncertainties for the dust composition. The crystallinity fractions with respect to the amorphous phases are different (higher crystallinity fractions), but the observed trends between crystalline (or amorphous) grains are still valid. All the results and conclusions discussed in the rest of the study therefore remain unchanged.

Source

Cite

Citations (0)

Dust around nearby stars (dunes): Description of the project and results.

B. Montesinos C. Eiroa Olivier Absil D. R. Ardila J.‐C. Augereau

DUNES is an Open Time Key Programme of the Herschel Space Observatory aimed at detecting and studying cold dusty -debris- discs, i.e. Kuiper-belt analogues, around FGK stars of the solar neighbourhood, in a volume-limited sample of 133 stars. The sensitivity and wavelengths of the two instruments used, namely PACS (70, 100, and 160 µm) and SPIRE (250, 350, and 500 µm) are the appropriate ones for these tasks. Debris discs are the result of collisions of planetesimals formed at early stages of the star formation episode, when the star is younger than about 30 Myr, and the discs, so-called protoplanetary, are composed of gas and dust. The whole sample is already observed and the team is currently analysing the data. We outline here some of the main results we have found.

Debris disk

Virtual Observatory

Source

Cite

Citations (0)

The effect of anisotropy on cross section spectra of uniaxial spherical particles small compared to the wavelength

Journal of Quantitative Spectroscopy and Radiative Transfer (2020)

Sonja Höfer H. Mutschke Th.G. Mayerhöfer

Ray

Spherical shell

Extinction (optical mineralogy)

Absorption cross section

10.1016/j.jqsrt.2020.106909

Cite

Citations (3)

Interstellar oxygen along the line of sight of Cygnus X-2

Astronomy and Astrophysics (2020)

I. Psaradaki E. Costantini M. Mehdipour Daniele Rogantini C. P. de Vries

Interstellar dust permeates our Galaxy and plays an important role in many physical processes in the diffuse and dense regions of the interstellar medium. High-resolution X-ray spectroscopy, coupled with modelling based on laboratory dust measurements, provides a unique probe to investigate the interstellar dust properties along our line of sight towards Galactic X-ray sources. Here, we focus on the oxygen content of the interstellar medium through its absorption features in the X-ray spectra. To model the dust features, we perform a laboratory experiment using the electron microscope facility located at the University of Cadiz in Spain, where we acquire new laboratory data in the oxygen K-edge. We study 18 dust samples of silicates and oxides with different chemical compositions. The laboratory measurements are adopted for our astronomical data analysis. We carry out a case study on the X-ray spectrum of the bright low-mass X-ray binary Cygnus X-2, observed by XMM-Newton. We determine different temperature phases of the ISM, and parameterize oxygen in both gas (neutral and ionised) and dust form. We find Solar abundances of oxygen along the line of sight towards the source. Due to both the relatively low depletion of oxygen into dust form and the shape of the oxygen cross section profiles, it is challenging to determine the precise chemistry of interstellar dust. However, silicates provide an acceptable fit. Finally, we discuss the systematic discrepancies in the atomic (gaseous phase) data of the oxygen edge spectral region using different X-ray atomic databases, and also consider future prospects for studying the ISM with the Arcus concept mission.

Line (geometry)

Line-of-sight

Extinction (optical mineralogy)

Forbidden mechanism

10.1051/0004-6361/202038749

Cite

Citations (14)

Solid-State Spectroscopy: Silicates & Carbonaceous Grains

The Molecular Universe (2011)

Christian Jäger H. Mutschke Thomas Henning F. Huisken

Source

Cite