Estimating the p-mode frequencies of the solar twin 18 Scorpii CAUP Researchers: Michaël Bazot, Tiago J. L. C. E. Campante, Xavier Dumusque, Mário J. P. F. G. Monteiro, Nuno C. Santos, Sérgio A. G. Sousa Team at CAUP: Origin and Evolution of Stars and Planets 2012