Search Publications
The GJ 504 system revisited. Combining interferometric, radial velocity, and high contrast imaging data
Kuzuhara, M.; Tamura, M.; Rouan, D. +79 more
Context. The G-type star GJ504A is known to host a 3-35 MJup companion whose temperature, mass, and projected separation all contribute to making it a test case for planet formation theories and atmospheric models of giant planets and light brown dwarfs.
Aims: We aim at revisiting the system age, architecture, and companion physica…
Stellar population of the superbubble N 206 in the LMC. II. Parameters of the OB and WR stars, and the total massive star feedback
Hamann, W. -R.; Gallagher, J. S.; Oskinova, L. M. +5 more
Context. Clusters or associations of early-type stars are often associated with a "superbubble" of hot gas. The formation of such superbubbles is caused by the feedback from massive stars. The complex N 206 in the Large Magellanic Cloud (LMC) exhibits a superbubble and a rich massive star population.
Aims: Our goal is to perform quantitative …
Coupling hydrodynamics with comoving frame radiative transfer. II. Stellar wind stratification in the high-mass X-ray binary Vela X-1
Hamann, W. -R.; Oskinova, L. M.; Sander, A. A. C. +5 more
Context. Vela X-1, a prototypical high-mass X-ray binary (HMXB), hosts a neutron star (NS) in a close orbit around an early-B supergiant donor star. Accretion of the donor star's wind onto the NS powers its strong X-ray luminosity. To understand the physics of HMXBs, detailed knowledge about the donor star winds is required.
Aims: To gain a r…
Stellar population of the superbubble N 206 in the LMC. I. Analysis of the Of-type stars
Hamann, W. -R.; Gallagher, J. S.; Oskinova, L. M. +5 more
Context. Massive stars severely influence their environment by their strong ionizing radiation and by the momentum and kinetic energy input provided by their stellar winds and supernovae. Quantitative analyses of massive stars are required to understand how their feedback creates and shapes large scale structures of the interstellar medium. The gi…
Global hot-star wind models for stars from Magellanic Clouds
Krtička, J.; Kubát, J.
We provide mass-loss rate predictions for O stars from Large and Small Magellanic Clouds. We calculate global (unified, hydrodynamic) model atmospheres of main sequence, giant, and supergiant stars for chemical composition corresponding to Magellanic Clouds. The models solve radiative transfer equation in comoving frame, kinetic equilibrium equati…
The shortest-period Wolf-Rayet binary in the Small Magellanic Cloud: Part of a high-order multiple system. Spectral and orbital analysis of SMC AB 6
Sander, A.; Hamann, W. -R.; Oskinova, L. M. +8 more
Context. SMC AB 6 is the shortest-period (P = 6.5 d) Wolf-Rayet (WR) binary in the Small Magellanic Cloud. This binary is therefore a key system in the study of binary interaction and formation of WR stars at low metallicity. The WR component in AB 6 was previously found to be very luminous (log L = 6.3 [L⊙]) compared to its reported or…
Metal abundances in hot white dwarfs with signatures of a superionized wind
Rauch, T.; Werner, K.; Kruk, J. W.
About a dozen hot white dwarfs with effective temperatures Teff = 65 000-120 000 K exhibit unusual absorption features in their optical spectra. These objects were tentatively identified as Rydberg lines of ultra-high excited metals in ionization stages v-x, indicating line formation in a dense environment with temperatures near 10…
Short-term variability and mass loss in Be stars. IV. Two groups of closely spaced, approximately equidistant frequencies in three decades of space photometry of ν Puppis (B7-8 IIIe)
Wang, L.; Handler, G.; Carciofi, A. C. +13 more
Context. In early-type Be stars, groups of nonradial pulsation (NRP) modes with numerically related frequencies may be instrumental for the release of excess angular momentum through mass-ejection events. Difference and sum/harmonic frequencies often form additional groups.
Aims: The purpose of this study is to find out whether a similar freq…
Large Interstellar Polarisation Survey. II. UV/optical study of cloud-to-cloud variations of dust in the diffuse ISM
Siebenmorgen, R.; Bagnulo, S.; Cox, N. L. J. +3 more
It is well known that the dust properties of the diffuse interstellar medium exhibit variations towards different sight-lines on a large scale. We have investigated the variability of the dust characteristics on a small scale, and from cloud-to-cloud. We use low-resolution spectro-polarimetric data obtained in the context of the Large Interstellar…
A quantitative NLTE analysis of visual and ultraviolet spectra of four helium-rich subdwarf O stars
Heber, U.; Latour, M.; Irrgang, A. +4 more
Aims: Hot subdwarf stars represent a poorly understood late phase of stellar evolution. While binary evolution plays an important role for the formation of B-type subdwarfs (sdB), the origin of the helium dominated subclass of O-type subdwarfs (He-sdO) is still unknown. We search for chemical signatures of their genesis by means of quantitati…