Preliminary results on ? Dor and d Sct-? Dor hybrids in the CoRoT exo-field of LRa01

The 131 days long, high-precision light curves observed in the CoRoT exo-field during LRa01 were investigated for ? Dor and d Sct-? Dor hybrid stars. In total 418 ? Dor and 274 d Sct-? Dor hybrid candidates were identified. For a fraction of these candidates spectra are available obtained at the Anglo-Australian Observatory. Effective temperatures and surface gravity were derived by fitting synthetic spectra of three Balmer lines, i.e. Ha, H beta, and H?, as well as of the Ca K line at 3933 degrees A. The bona fide ? Dor and hybrid stars were plotted in an Teff- log g diagram that shows the expected concentration of ? Dor stars at the cool border of the d Sct strip. In contrast, the hybrids fill the whole d Sct instability strip without a noticeable concentration. Remarkably, the fraction of constant stars, with no signal above 3 times the noise level, is smallest in the same temperature regime ((c) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)