BONANNO, Alfio MaurizioAlfio MaurizioBONANNO2020-05-202020-05-2020160004-637Xhttp://hdl.handle.net/20.500.12386/24999Recent spectro-polarimetric observations of solar-type stars have shown the presence of photospheric magnetic fields with a predominant toroidal component. If the external field is assumed to be current-free it is impossible to explain these observations within the framework of standard mean-field dynamo theory. In this work, it will be shown that if the coronal field of these stars is assumed to be harmonic, the underlying stellar dynamo mechanism can support photospheric magnetic fields with a prominent toroidal component even in the presence of axisymmetric magnetic topologies. In particular, it is argued that the observed increase in the toroidal energy in low-mass fast-rotating stars can be naturally explained with an underlying αΩ mechanism.STAMPAenArticle10.3847/2041-8213/833/2/L222-s2.0-85007023044000393434600001https://iopscience.iop.org/article/10.3847/2041-8213/833/2/L22/meta2016ApJ...833L..22BFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation