Reconstruction of total solar irradiance variability as simultaneously apparent from Solar Orbiter and Solar Dynamics Observatory
Schmidt, W.; Woch, J.; Solanki, S. K.; Schou, J.; Fiethe, B.; Yeo, K. L.; Krivova, N. A.; Bellot Rubio, L. R.; Appourchaux, T.; Valori, G.; Heerlein, K.; del Toro Iniesta, J. C.; Gizon, L.; Calchetti, D.; Moreno Vacas, A.; Hirzberger, J.; Albert, K.; Albelo Jorge, N.; Blanco Rodríguez, J.; Feller, A.; Gandorfer, A.; García Parejo, P.; Gutierrez-Marques, P.; Kahil, F.; Kolleck, M.; Korpi-Lagg, A.; Orozco Suárez, D.; Pérez-Grande, I.; Sanchis Kilders, E.; Sinjan, J.; Staub, J.; Strecker, H.; Volkmer, R.; Alvarez-Herrero, A.; Balaguer Jiménez, M.; Carmona, M.; Fernández-Medina, A.; Grauf, B.; Maue, T.; Meller, R.; Müller, R.; Nakai, E.; Torralbo, I.; Fernandez-Rico, G.; Gasent Blesa, J. L.
Germany, Spain, France
Abstract
Solar irradiance variability has been monitored almost exclusively from the Earth's perspective. We present a method to combine the unprecedented observations of the photospheric magnetic field and continuum intensity from outside the Sun-Earth line, which is being recorded by the Polarimetric and Helioseismic Imager on board the Solar Orbiter mission (SO/PHI), with solar observations recorded from the Earth's perspective to examine the solar irradiance variability from both perspectives simultaneously. Taking SO/PHI magnetograms and continuum intensity images from the cruise phase of the Solar Orbiter mission and concurrent observations from the Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory (SDO/HMI) as input into the SATIRE-S model, we successfully reconstructed the total solar irradiance variability as apparent from both perspectives. In later stages of the SO mission, the orbital plane will tilt in such a way as to bring the spacecraft away from the ecliptic to heliographic latitudes of up to 33°. The current study sets the template for the reconstruction of solar irradiance variability as seen from outside the ecliptic from data that SO/PHI is expected to collect from such positions. Such a reconstruction will be beneficial to factoring inclination into how the brightness variations of the Sun compare to those of other cool stars, whose rotation axes are randomly inclined.