Journal: Astronomy and Astrophysics

  • Publication
    Fundamental parameters of galactic luminous OB stars. II. A spectroscopic analysis of HDE 226868 and the mass of Cygnus X-1.
    We present a spectroscopic analysis of the O9.7 Iab star HDE 226868, which is the optical counterpart of Cygnus X-1. We use this extreme supergiant to test the...
  • Publication
    Fundamental parameters of galactic luminous OB stars. III. Spectroscopic analysis of O stars in Cygnus OB2
    We present the results of the spectral analysis of 11 OB stars in Cyg OB2, among them seven giants and supergiants. The projected rotational velocities of these...
  • Publication
    Fundamental parameters of Galactic luminous OB stars. IV. The upper HR diagram
    We present observations and analyses of seven Galactic O stars of type O6 and earlier. The analyses are carried out using NLTE plane-parallel, hydrostatic...
  • Publication
    Fundamental parameters of Galactic luminous OB stars. V. The effect of microturbulence
    We study the effect of microturbulence in the line formation calculations of H and He lines, in the parameter range typical for O and early B stars. We are...
  • Publication
    Fundamental parameters of massive stars in multiple systems: The cases of HD 17505A and HD 206267A
    Context. Many massive stars are part of binary or higher multiplicity systems. The present work focusses on two higher multiplicity systems: HD 17505A and HD...
  • Publication
    Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures
    The Hipparcos mission has made it possible to constrain the positions of nearby field stars in the colour-magnitude diagram with very high accuracy. These...
  • Publication
    Fundamental physics with ESPRESSO: Constraining a simple parametrisation for varying α
    Context. The spectrograph ESPRESSO recently obtained a limit on the variation of the fine-structure constant, α, through measurements along the line of sight of...
  • Publication
    Fundamental physics with ESPRESSO: Precise limit on variations in the fine-structure constant towards the bright quasar HE 0515−4414
    The strong intervening absorption system at redshift 1.15 towards the very bright quasar HE 0515−4414 is the most studied absorber for measuring possible...
  • Publication
    Fundamental physics with ESPRESSO: Towards an accurate wavelength calibration for a precision test of the fine-structure constant
    Observations of metal absorption systems in the spectra of distant quasars allow one to constrain a possible variation of the fine-structure constant throughout...