European Solar Physics Online Seminar Archive

Stellar flares cannot be spatially resolved, which means that we have to extract complex three-dimensional behavior from a one-dimensional disk-integrated spectrum. Due to their proximity to Earth, solar flares can serve as a stepping stone for understanding their stellar counterparts, especially when using a Sun-as-a-star instrument in combination with spatially resolved observations. In this talk I will discuss a confined X2.2 flare and its eruptive X9.3 successor as measured by the HARPS-N Sun-as-a-star telescope. The behavior of multiple photospheric and chromospheric spectral lines are investigated by means of activity indices and contrast profiles, which are then related to physical processes directly observed in high-resolution observations made with the Swedish 1-meter Solar Telescope (SST). We further explore these relations by using the newly developed Numerical Sun-as-a-Star Integrator (NESSI) code to convert high-resolution SST flares to full disk spectra. Our findings suggest a relationship between the evolving shapes of the disk integrated spectra and the flare locations on the solar disk, which could be act as a guide for constraining flare locations in stellar spectra. [more]