Stellar flares observed by LOFT: implications for the physics of coronae and for the "space weather" environment of extrasolar planets

PreambleThe Large Observatory for X-ray Timing, LOFT , is designed to perform fast X-ray timing and spectroscopywith uniquely large throughput (Feroci et al. 2014). LOFT focuses on two fundamental questions ofESA's Cosmic Vision Theme “Matter under extreme conditions”: what is the equation of state of ultra-dense matter in neutron stars? Does matter orbiting close to the event horizon follow the predictions ofgeneral relativity? These goals are elaborated in the mission Yellow Book ( http://sci.esa.int/loft/53447-loft-yellow-book/ ) describing the LOFT mission as proposed in M3, which closely resemblesthe LOFT mission now being proposed for M4.The extensive assessment study of LOFT as ESA's M3 mission candidate demonstrates the high levelof maturity and the technical feasibility of the mission, as well as the scientic importance of its uniquecore science goals. For this reason, the LOFT development has been continued, aiming at the new M4launch opportunity, for which the M3 science goals have been conrmed. The unprecedentedly largee ective area, large grasp, and spectroscopic capabilities of LOFT 's instruments make the mission capableof state-of-the-art science not only for its core science case, but also for many other open questions inastrophysics.LOFT 's primary instrument is the Large Area Detector (LAD), a 8:5m