Search Publications
Clumping and X-rays in cooler B supergiant stars
Bouret, J. -C.; Oskinova, L. M.; Sander, A. A. C. +6 more
Context. B supergiants (BSGs) are evolved stars with effective temperatures between ~10 to ~30 kK. Knowing the properties of these objects is important to understand massive star evolution. Located on the cool end of the line-driven wind regime, the study of their atmospheres can help us to understand the physics of their winds and phenomena such …
Surface chemical composition of single WNh stars
Martins, Fabrice
Context. Wolf-Rayet (WR) stars of the WNh category contain a significant fraction of hydrogen at their surface. They can be hydrogen-burning, very massive stars or stars in a post-main sequence phase of evolution. Also, WNh stars are sometimes not included in population synthesis models.
Aims: We aim to better characterise the properties of s…
Quantitative spectroscopy of late O-type main-sequence stars with a hybrid non-LTE method
Butler, K.; Przybilla, N.; Aschenbrenner, P.
Context. Late O-type stars at luminosities log L/L⊙ ≲ 5.2 show weak winds with mass-loss rates lower than 10−8 M⊙ yr−1. This implies that, unlike their more massive and more luminous siblings, their photospheric layers are not strongly affected by the stellar wind.
Aims: A hybrid non-local thermodyn…
The blue supergiant Sher 25 revisited in the Gaia era
Butler, K.; Weßmayer, D.; Przybilla, N. +2 more
Aims: The evolutionary status of the blue supergiant Sher 25 and its membership to the massive cluster NGC 3603 are investigated.
Methods: A hybrid non-local thermodynamic equilibrium (non-LTE) spectrum synthesis approach is employed to analyse a high-resolution optical spectrum of Sher 25 and five similar early B-type comparison stars i…
Dark dust. III. The high-quality single-cloud reddening curve sample: Scrutinizing extinction curves in the Milky Way
Krełowski, J.; Siebenmorgen, R.; Chini, Rolf +2 more
The nature of dust in the diffuse interstellar medium can be best investigated by means of reddening curves where only a single interstellar cloud lies between the observer and the background source. Published reddening curves often suffer from various systematic uncertainties. We merged a sample of 820 reddening curves of stars for which both FOR…
Infrared He I 10830 Å, ultra-violet Ca II, and Mg II chromosphere emissions in the spectra of classical Cepheid X Cyg
Korotin, S. A.; Andrievsky, S. M.; Kovtyukh, V. V.
Aims: In a previous publication, we reported the first detection of emission in the infrared (IR) triplet at 10 830 Å in the spectra of the classical Cepheid X Cyg. Emission is detectable at phases from approximately 0.25 to 0.90. We present and discuss further information on the chromosphere activity of this star, namely International Ultrav…
Structure of the accretion flow of IX Velorum as revealed by high-resolution spectroscopy
Pala, A. F.; Schmidtobreick, L.; Kára, J. +1 more
Context. Several high mass-transfer cataclysmic variables show evidence of outflow from the system, which could play an important role in their evolution. We investigate the system IX Vel, which was proposed to show similar characteristics.
Aims: We study the structure of the IX Vel system, particularly the structure of its accretion flow and…
Analysis of the first coronagraphic multi-band observations of a sungrazing comet
Heinzel, P.; Sasso, C.; Romoli, M. +35 more
Context. Between 24 and 25 December 2021 a sungrazing comet (SOHO-4341) approached the Sun, being observed by "classical" visible light (VL) coronagraphs on board the SOHO and STEREO missions, and also by the innovative Metis coronagraph on board the ESA-NASA Solar Orbiter mission in the VL and ultraviolet (UV H I Lyman-α) band.
Aims: We show…