The spectra used for classifying the stars of our sample were obtained with the same instrument as
the MK standards of Paper I. The stars were observed with the 193 cm
telescope of the Observatoire de Haute-Provence (OHP): the spectra were obtained with the CARELEC spectrograph and a
CCD receiver Thomson (
pixels) or Tectronix (
pixels). The grating permits to
obtain 33 Å/mm spectra over a wavelength interval of 400 Å with a
resolution close to 2 Å/mm. The
spectra were reduced and measured with the IHAP software available
at the OHP.