Reconstruction of total solar irradiance variability as simultaneously apparent from Solar Orbiter and Solar Dynamics Observatory

TL;DR

This study combines observations from Solar Orbiter and SDO to reconstruct the total solar irradiance variability from both Earth's and outside perspectives, aiding understanding of solar brightness variations.

Contribution

It introduces a method to simultaneously analyze solar irradiance variability from multiple viewpoints using data from SO/PHI and SDO/HMI with the SATIRE-S model.

Findings

Successful reconstruction of solar irradiance variability from dual perspectives.

Method sets a template for future outside-ecliptic observations.

Facilitates comparison of solar brightness with other stars.

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 $33^{\circ}$. 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.