107 citations · 346 across the 12 of their papers we have counts for
9 papers · 1 filter
Chromospheric activity and photospheric variation of Ori during the great dimming event in 2020
M. Mittag, K. -P. Schröder, V. Perdelwitz +2
The so-called great dimming event of alpha Ori in late 2019 and early 2020 sparked our interest in the behaviour of chromospheric activity during this period. To study the timeline…
Simultaneous X-ray and optical spectroscopy of the Oef supergiant lambda Cep
G. Rauw, A. Herve, Y. Naze +8
Probing the structures of stellar winds is of prime importance for the understanding of massive stars. Based on their optical spectral morphology and variability, the stars of the…
Spectroscopic variability of two Oe stars
G. Rauw, T. Morel, Y. Naze +28
The Oe stars HD45314 and HD60848 have recently been found to exhibit very different X-ray properties: whilst HD60848 has an X-ray spectrum and emission level typical of most OB sta…
The Magnetic Fields at the Surface of Active Single G-K Giants
M. Aurière, R. Konstantinova-Antova, C. Charbonnel +15
We investigate the magnetic field at the surface of 48 red giants selected as promising for detection of Stokes V Zeeman signatures in their spectral lines. We use the spectropolar…
Habitability around F-type Stars
S. Sato, M. Cuntz, C. M. Guerra Olvera +2
We explore the general astrobiological significance of F-type main-sequence stars with masses between 1.2 and 1.5 Msun. Special consideration is given to stellar evolutionary aspec…
Magnetic fields in single late-type giants in the Solar vicinity: How common is magnetic activity on the giant branches?
R. Konstantinova-Antova, M. Aurière, C. Charbonnel +6
We present our first results on a new sample containing all single G,K and M giants down to V = 4 mag in the Solar vicinity, suitable for spectropolarimetric (Stokes V) observation…
Basal Chromospheric Flux and Maunder Minimum-type Stars: The quiet-Sun Chromosphere as a Universal Phenomenon
K. -P. Schroeder, M. Mittag, M. I. Perez Martinez +2
Aims: We demonstrate the universal character of the quiet-Sun chromosphere among inactive stars (solar-type and giants). By assessing the main physical processes, we shed new light…
Near-infrared spectro-interferometry of three OH/IR Stars with the VLTI/AMBER instrument
A. E. Ruiz-Velasco, M. Wittkowski, A. Wachter +2
We investigate the molecular and dusty environment of OH/IR stars in order to characterize the mass-loss process during the tip-AGB superwind phase. Employing the AMBER instrument…
Direct detection of a magnetic field in the photosphere of the single M giant EK Boo: How common is magnetic activity among M giants?
R. Konstantinova-Antova, M. Auriere, C. Charbonnel +6
We study the fast rotating M5 giant EK Boo by means of spectropolarimetry to obtain direct and simultaneous measurements of both the magnetic field and activity indicators, in orde…