Joachim Wiegert

Joachim Wiegert
Uppsala University | UU · Department of Physics and Astronomy

Doctor of Philosophy

About

10
Publications
771
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
256
Citations
Citations since 2016
3 Research Items
199 Citations
201620172018201920202021202201020304050
201620172018201920202021202201020304050
201620172018201920202021202201020304050
201620172018201920202021202201020304050
Introduction
My research interests are circumstellar dust, exoplanets and stellar physics. My research focus is on radiative transer simulations through circumstellar dust for theoretical studies and comparisons with data. My PhD was on debris discs of nreaby sun-like stars, in collaboration with DUNES. In my postdocs I have worked on dust around AGB-stars. In Brussels, Belgium I worked in the STARLAB project, and I recently started a postdoc in the EXWINGS project in Uppsala, Sweden.
Additional affiliations
May 2018 - June 2019
Royal Observatory of Belgium
Position
  • PostDoc Position
September 2011 - September 2016
Chalmers University of Technology
Position
  • PhD Student
October 2009 - December 2010
University of Gothenburg
Position
  • Master's Student

Publications

Publications (10)
Preprint
Full-text available
Context. High-angular-resolution observations of asymptotic giant branch (AGB) stars often reveal non-spherical morphologies for the gas and dust envelopes. Aims. We aim to make a pilot study to quantify the impact of different geometries (spherically symmetric, spiral-shaped, and disc-shaped) of the dust component of AGB envelopes on spectral ener...
Article
Full-text available
Low and intermediate mass stars evolve to the asymptotic red giant branch (AGB) late in their lives. These are surrounded by a circumstellar envelope (CSE) filled with gas and dust. The dust is formed close to the star at sublimation radii and is pushed away by the stellar wind. The dust in turn pushes gases from the envelope into the interstellar...
Article
Full-text available
94 Ceti is a triple star system with a circumprimary gas giant planet and far-infrared excess. Such excesses around main sequence stars are likely due to debris discs, and are considered as signposts of planetary systems and, therefore, provide important insights into the configuration and evolution of the planetary system. Consequently, in order t...
Article
We present ultraviolet (UV) observations of six nearby Type Ia supernovae (SNe Ia) obtained with the Hubble Space Telescope, three of which were also observed in the near-IR (NIR) with Wide-Field Camera 3. UV observations with the Swift satellite, as well as ground-based optical and NIR data provide complementary information. The combined data set...
Article
Full-text available
Context. Debris discs around main-sequence stars indicate the presence of larger rocky bodies. The components of the nearby, solar-type binary α Centauri have metallicities that are higher than solar, which is thought to promote giant planet formation. Aims. We aim to determine the level of emission from debris around the stars in the α Cen system....
Article
We report the following supernova classifications. Targets were supplied by the Catalina Sky Survey (http://nesssi.cacr.caltech.edu/catalina/Allns.html). All observations were made with the Nordic Optical Telescope, during the night starting on 2013 May 24, using ALFOSC, grism 4 (320-910 nm, 16 Å resolution) and 1" slit. Classifications were done w...
Article
Full-text available
Context. Chromospheres and coronae are common phenomena on solar-type stars. Understanding the energy transfer to these heated atmospheric layers requires direct access to the relevant empirical data. Study of these structures has, by and large, been limited to the Sun thus far. Aims. The region of the temperature reversal can be directly observed...
Article
Full-text available
Chromospheres and coronae are common phenomena on solar-type stars. Understanding the energy transfer to these heated atmospheric layers requires direct access to the relevant empirical data. Study of these structures has, by and large, been limited to the Sun thus far. The region of the temperature reversal can be directly observed only in the far...
Article
Full-text available
The Wang-Silk approximation, 1/Q ~ 1/Q_stars + 1/Q_gas, is frequently used for estimating the effective Q parameter in two-component discs of stars and gas. Here we analyse this approximation in detail, and show how its accuracy depends on the radial velocity dispersions and Toomre parameters of the two components. We then propose a much more accur...

Network

Cited By