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Almost three decades ago, Mathys (1990) demonstrated the importance of studying Ap stars showing resolved Zeeman split Fe II 6147.7 and 6149.2 lines. Such Zeeman split lines can be seen in stars whose projected rotational velocity is sufficiently small and whose magnetic field is strong enough to exceed the rotational Doppler broadening. Observations of resolved Zeeman split lines permit the diagnosis of the average of the modulus of the magnetic field over the visible stellar hemisphere. Although Zeeman splitting is not expected in faster rotating hot massive stars, we have recently been discovering early B-type stars displaying magnetically split spectral lines.
Previously unrecognized weak emission lines originating from high excitation states of Si II (12.84 eV) and Al II (13.08 eV) are detected in the red region spectra of slowly rotating early B-type stars. We surveyed high resolution spectra of 35 B-typ
The powerful radiative winds of hot stars with strong magnetic fields are magnetically confined into large, corotating magnetospheres, which exert important influences on stellar evolution via rotational spindown and mass-loss quenching. They are det
The first two of a total of six nano-satellites that will constitute the BRITE-Constellation space photometry mission have recently been launched successfully. In preparation for this project, we carried out time-resolved colour photometry in a field
We summarize the properties of the new periodic, small amplitude, variable stars recently discovered in the open cluster NGC 3766. They are located in the region of the Hertzsprung-Russell diagram between delta Sct and slowly pulsating B stars, a reg
Aims. To explore the chemical pattern of early-type stars with planets, searching for a possible signature of planet formation. In particular, we study a likely relation between the lambda Bootis chemical pattern and the presence of giant planets. Me