Thun, Kuiper, Schmidt, Kley (2016)



My Team and I are developing novel numerical algorithms for hydrodynamics simulations in the framework of high-performance computing. Besides fluid motion, simulations include gravity, magnetic fields, continuum radiation transport, photoionization, phase transitions, chemical evolution, stellar evolution, and dust evolution. We apply these tools to model specific astrophysical processes, focussing on accretion and ejection phenomena, and addressing open research questions within a broad spectrum of topics. Our research interests range from planet and star formation, to accretion disks, to stellar physics and stellar feedback, to planetary atmospheres and exoplanets, to the turbulent interstellar medium, to black hole formation, active galactic nuclei, gamma-ray bursts, and to the physics of the early Universe. 

Image Credit: Shanghuo Li, MPIA / Data: ALMA Observatory

Multiple birth of stars

Researchers have long assumed that massive stars are born as twins, triplets or even higher multiple systems. Now, for the first time, this has been confirmed by systematic observations. The study, in which our research group was involved in the interpretation of the data obtained, was published in Nature Astronomy.

More information (in German) at:

The scientific article:

Image Credit: ESO/M. Kornmesser, Article: McLeod et al. (2023)

Astronomers discover a disk around a star in another galaxy for the first time

A remarkable discovery: Together with a team of international scientists, we have discovered a disk around a young star in the Large Magellanic Cloud, a neighboring galaxy to Earth. It is the first time that such a disk has been found outside our galaxy. The new observations show a massive young star that is growing, absorbing matter from its surroundings and forming a rotating disk. The discovery was made with the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.

More information:

The scientific article: 


Nature Astronomy Cover Page, Volume 6 Issue 9, September 2022; Image: Image courtesy of André Oliva. Cover: Bethany Vukomanovic.

Watching the wind blow

This cover page of Nature Astronomy from September 2022 highlights one of our numerical projects on magnetically-driven jets ejected from massive proto-stars.

In this article, our complementary radiation-magneto-hydrodynamic simulations are visually and quantitatively compared to an observed spiralling flow of plasma. This flow structure is expected for a helical magnetic field geometry forming during cloud collapse, star and circumstellar disk formation. 

The observational data is obtained from high-spatial-resolution observations of water masers around the young massive proto-star IRAS21078+5211. To reach this kind of breakthrough spatial resolution, we made use of all telescopes available in the Very Large Baseline Interferometer network (VLBI). The VLBI array combines 26 radio-telescopes distributed across Europe, Asia and the USA.

Red dots are the observed maser spot locations, the bright white circle denotes the expected position of the massive proto-star. Blue-to-white background color resembles the gas mass density obtained from numerical simulations and shows the circumstellar disk forming from infalling material from larger scales. Blue lines present the spiraling streamlines of the gas flow obtained from the numerical simulation.

See Moscadelli et al. (2022)  for further details.


Rolf Kuiper

- Group Leader -

MC 346

+49 (0) 203 37 91684

rolf.kuiper @

Ingo Thiele

- Administration -

MC 373

+49 (0) 203 37 92816

ingo.thiele @

Lothar Brendel

- Research Assistant -

MC 342

+49 (0) 203 37 91688

lothar.brendel @

Vardan Elbakyan

- Postdoc -

MC 343

+49 (0) 203 37 94227


Hiroto Mitani

- Postdoc -

MC 346

+49 (0) 203 37 91684

Luke Conmy

- PhD -

MC 363

+49 (0) 203 37 91680

Frederike Marx

- PhD -

MC 362

+49 (0) 203 37 93321

Mohaddeseh (Moha) Mousavi

- PhD -

MC 363

+49 (0) 203 37 91680

Dennis Wehner

- PhD -

MC 362

+49 (0) 203 37 93321

dennis.wehner @

 Shaghayegh Ashtari Jolehkaran

- Master -

MC 344

+49 (0) 203 37 91578

shaghayegh.ashtari-jolehkaran @

Arthur Langer

- Master -

MC 346

+49 (0) 203 37 91684

Marek Schulze

- Master Energy Science -

MC 344

+49 (0) 203 37 91578

claas.schulze @

 Joshua Barquero Alvarado

- Master (University of Costa Rica) -

joshua.barquero @

Marvin Henke

- Bachelor -

MC 374

+49 (0) 203 37 93824

Emilio Schmidt

- Bachelor -

MC 374

+49 (0) 203 37 93824

Lena Schürmann

- Bachelor -

MC 374

+49 (0) 203 37 93824

Fynn Luca Wawrzyniak

- Bachelor -

MC 374

+49 (0) 203 37 93824

Formally associated with this WG

Florian Führer

- PhD (WG Wolf) -

MC 343

+49 (0) 203 37 91683

florian.fuehrer @

Ana Vila Verde

- Group Leader WG "Computational Soft Matter and Interfaces" -

MF 246

+49 (0) 203 37 94716

ana.araujo-vila-verde @

WG Vila Verde

MF 245

+49 (0) 203 37 92137

Elio Casalini

Suleyman Skoko

Former Members



Tobias Moldenhauer

Jin-Jun Geng

Nathaniel Dylan Kee

Dominique Meyer



Lukas Engelke

Magdulin Dwedari

André Oliva

Tobias Moldenhauer

Asmita Bhandare

Anders Kölligan



Dennis Wehner

Lauren Martini

Marius Morlock

Oliver Völkel

Akram Chaalali

Daniel Thun



Robin Simbeck

Maximilian Wykidanez

Richard Nies

Prateek Boga (@ SASTRA University)

Nicolas Cimerman

Oliver Völkel



Aswathi Krishnan Kutty

Mustafa Waqar Syed

Shyam Harimohan Menon

Timothy Hallatt


Research Topics


The research topics of our group spans from the interaction physics of dust grains with high-velocity gas flows and radiation to planet formation, star formation, and black hole formation. Besides formation/accretion phenomena, we are also interested in ejection and feedback phenomena in space. In the following, we briefly present some of these topics.

Moldenhauer, Kuiper et al. (2021); sketch by André Oliva

Planet Formation

How does a rocky planetary embrio accrete its primordial gaseous atmosphere from the natal circumstellar disk? What is the final mass, temperature and angular momentum of the gas bound to the rocky core? Under which conditions does the proto-planet evolve into a gas giant? 

We investigate these questions and associated issues in modern planet formation theory by direct numerical simulations of the accretion process (see sketch "Moldenhauer, Kuiper et al. (2021)"). Making use of high-performance computing resources, we embed a gravitationally acting rocky planetary core into a gaseous circumstellar disk and follow the hydrodynamic and thermodynamic evolution of the system in time.

sketch by André Oliva

Star Formation and High-Mass Stellar Feedback

How much mass can a star gain by classical gas accretion? How does its intrinsic feedback mechanisms such as proto-stellar jets, radiation pressure, photoionization feedback and H II regions impede its further growth? How do these feedback effects impact the natal environment of the forming massive star?

We investigate these questions and associated issues in modern star formation theory by direct numerical simulations of the star formation process including the various forms of feedback. Most of the feedback effects can be investigated self-consistently, i.e. they are included in the formation scenario via solving for their underlying physical origin such as the magneto-hydrodynamics of jet launching, acceleration, collimation, and propagation.

Besides the feedback mechanisms, we are interested in the details of circumstellar disk formation and evolution, determining the  accretion efficiency of the forming host star. What is the impact of the large-scale environment on specific disk properties? How does disk formation and evolution differ across the stellar mass range?

Velocity structure of a van Kármán vortex street forming behind a cylinder embedded in a subsonic flow.

Numerical Wind Tunnel Experiments

In the context of general physics, we are performing numerical experiments of fluid flow structures around different kind of solid bodies in the sub-sonic and supersonic regime. In collaboration with the laboratory astrophysics research group of Prof. Dr. Gerhard Wurm, we are studying the erosion of planetesimals and the interaction of individual dust grains with gas flows.



Do the research topics above arouse your interest? Are you eager to carry out a project in computational astrophysics? If so, please do not hesitate to contact us and arrange a personal meeting to discuss mutual expectations, potential concerns, and your specific requirements. Let's chat about your favorite topics and methods, and think about the skills you want to employ or what you want to achieve during the project. Anyway, I am sure we will find a project matching your individual needs, skills, and interests!

Open PhD and Postdoc positions are usually published at the online job market of the Astronomische Gesellschaft ( and/or on the online job market of the American Astronomical Community (

Bachelor and Master projects are available year-round and will be organized during a personal meeting.

Internships for external students are possible as well, please just get in contact with us.



Link to group leader's publication lists (automatically created):

Rolf Kuiper @ NASA/ADS

Rolf Kuiper @ ORCiD

Rolf Kuiper @ Google Scholar



Some of our research involves visualization of the numerical simulations performed. More examples of such animations can be found on our YouTube channel:



Over the years, our research projects have been supported by a variety of grant funding schemes. We gratefully acknowledge financial support by the following institutions and programmes:



Prof. Dr. Rolf Kuiper (Group Leader)

rolf.kuiper @

Office: MC 377


Ingo Thiele (Administration)

ingo.thiele @

Phone: +49 203 379 2816

Fax: +49 203 379 1681

Office: MC 373



WG Kuiper

Faculty of Physics

University of Duisburg-Essen

Lotharstraße 1

D-47057 Duisburg



Arrival by train:

By foot: It takes about half an hour to get to our Campus from Duisburg Central Station.

By streetcar: You can get on the streetcar U-901 directly at Duisburg main station. The most direct way to reach the streetcar is not to leave the main station via the main exit, but to follow the signs to the U-901 directly at the platform. Then take the U-901 underground at platform 3 in the direction of "Mülheim an der Ruhr" or Duisburg "Zoo / Universität". After only a few minutes, get off at the "Zoo / Universität" stop. Our campus is then just a minute's walk away back in the opposite direction.