Cool Stars 14 - Submitted Abstract # 233 This version created on 05 October 2006 Active regions in a sample of late-type rapid rotator stars: spectroscopic analysis M. Magdalena Hernan-Obispo, Universidad Complutense de Madrid Elisa de Castro, Universidad Complutense de Madrid UCM - University of Florida Galvez M.Cruz Manuel Cornide, Universidad Complutense de Madrid David Montes, Universidad Complutense de Madrid High-resolution spectral and temporal echelle observations of late-type rapid rotator stars have been carried out along several runs using: SOFIN spectrograph at 2.56m Nordic Optical Telescope (NOT, La Palma), FOCES spectrograph in 2.2m Telescope at Calar Alto Observatory and SARG spectrograph at 3.58m Telescopio Nazionale Galileo (TNG, La Palma). The detailed analysis of spectra with high S/N can be use to detect the presence of active regions in different layers: spots on photosphere, plages and prominences on chromosphere and flares. In essence we search temporal variations on equivalent width and profile line asymmetry of different magnetic indicators (mainly Hα (6562.9 A) and Hb (4861 A)). Heliocentric radial velocity variations have been also determined. To study the radial velocity variations, the correlation with line bisectors of cross-correlated photospheric lines is calculated. In this contribution the applied method and main results are presented for BD+20 1790 . ----------------------------------