IAXO, next-generation of helioscopes

Abstract: The International Axion Observatory (IAXO) is a forth generation axion helioscope designed to detect solar axions and axion-like particles (ALPs) with a coupling to the photon $g_{a\gamma}$ down to a few $10^{-12}$ GeV$^{-1}$, 1.5 orders of magnitude beyond the current best astrophysical and experimental upper bounds. This range includes parameter values invoked in the context of the observed anomalies in light propagation over astronomical distances and to explain the excessive cooling observed in a number of stellar objects. Here we review the status of the IAXO project and of its potential to probe the most physically motivated regions of the axion/ALPs parameter space.