Poster abstract details
The influence of metallicity to the borders of the classical instability strip
Abstract
Light curves of gDor, dSct and gDor-dScut Hybrid stars observed during CoRoT IRa1, LRa1 and LRa2 were investigated. For the brighter stars in the sample low resolution classification spectra were obtained at the Anglo-Australian Observatory. For a total of 382 dSct, 290 gDor and 102 Hybrid candidate stars the fundamental parameters were derived and the stars positioned in a HRD.
Hybrid stars are not only confined to the overlapping region of the dSct-gDor instabillity strips, but are present all over the dSct strip. Additionally many gDor stars being cooler than the theoretical red edge of the gDor strip show low metallicity. In contrast gDor stars at the blue edge show higher metallicity and cool dSct stars in the overlapping area of both strips show lower metallicity. This suggests that the depth of the convective envelope, which changes with metallicity, plays an important role in the selection of the pulsation mechanism as is predicted by theory.
Hybrid stars are not only confined to the overlapping region of the dSct-gDor instabillity strips, but are present all over the dSct strip. Additionally many gDor stars being cooler than the theoretical red edge of the gDor strip show low metallicity. In contrast gDor stars at the blue edge show higher metallicity and cool dSct stars in the overlapping area of both strips show lower metallicity. This suggests that the depth of the convective envelope, which changes with metallicity, plays an important role in the selection of the pulsation mechanism as is predicted by theory.