40 citations · 77 across the 10 of their papers we have counts for
11 papers · 1 filter
An Halpha survey of infrared bow-shocks around OB-type stars
Kuljeet Singh Saddal, Michaela Kraus, Dieter H. Nickeler +3
Bow shocks (BSs) around massive stars are commonly identified in mid-infrared (MIR) surveys. In contrast, systematic optical investigations of these structures remain scarce with o…
Rings, shells, and arc structures around B[e] supergiants: I. Classical tools of non-linear hydrodynamics
Dieter H. Nickeler, Michaela Kraus
Structures in circumstellar matter reflect both fast processes and quasi-equilibrium states. A geometrical diversity of emitting circumstellar matter is observed around evolved mas…
Dense Molecular Environments of B[e] Supergiants and Yellow Hypergiants
Michaela Kraus, Michalis Kourniotis, Maria Laura Arias +2
Massive stars expel large amounts of mass during their late evolutionary phases. We aim to unveil the physical conditions within the warm molecular environments of B[e] supergiants…
Resolving the circumstellar environment of the Galactic B[e] supergiant star MWC 137. II. Nebular kinematics and stellar variability
Michaela Kraus, Tiina Liimets, Alexei Moiseev +4
The Galactic B[e] supergiant MWC 137 is surrounded by a large-scale optical nebula. To shed light on the physical conditions and kinematics of the nebula, we analyze the optical fo…
An Optimization Principle for Computing Stationary MHD Equilibria With Solar Wind Flow
Thomas Wiegelmann, Thomas Neukirch, Dieter H. Nickeler +1
In this work we describe a numerical optimization method for computing stationary MHD-equilibria. The newly developed code is based on a nonlinear force-free optimization principle…
Resolving the circumstellar environment of the Galactic B[e] supergiant star MWC 137 from large to small scales
Michaela Kraus, Tiina Liimets, Cristina E. Cappa +10
The Galactic object MWC 137 was suggested to belong to the group of B[e] supergiants. However, with its large-scale optical bipolar ring nebula and the high velocity jet and knots,…