Early-type stars observed in the ESO UVES Paranal Observatory Project - V. Time-variable interstellar absorption

  title={Early-type stars observed in the ESO UVES Paranal Observatory Project - V. Time-variable interstellar absorption},
  author={Catherine M. McEvoy and Jonathan V. Smoker and Philip L. Dufton and Keith T. Smith and Michael B. Kennedy and Francis P. Keenan and David L. Lambert and Daniel E. Welty and James Thomas Lauroesch},
  journal={Monthly Notices of the Royal Astronomical Society},
The structure and properties of the diffuse interstellar medium (ISM) on small scales, sub-au to 1 pc, are poorly understood. We compare interstellar absorption-lines, observed towards a selection of O- and B-type stars at two or more epochs, to search for variations over time caused by the transverse motion of each star combined with changes in the structure in the foreground ISM. Two sets of data were used: 83 VLT- UVES spectra with approximately 6 yr between epochs and 21 McDonald… 

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