Measuring the F-corona intensity through time correlation of total and polarized visible light images

¹ INAF – Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Florence, Italy
e-mail: aleksandr.burtovoi90@gmail.com
² Department of Physics and Astronomy, University of Padova, Via F. Marzolo 8, 35131 Padova, Italy
e-mail: giampiero.naletto@unipd.it
³ INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁴ INAF – Osservatorio Astrofisico di Catania, Via Santa Sofia 78, 95123 Catania, Italy
⁵ Department of Physics and Astronomy, University of Florence, Largo Enrico Fermi 2, 50125 Firenze, Italy
⁶ INAF – Osservatorio Astrofisico di Torino, Via Osservatorio, 20, 10025 Pino Torinese, Turin, Italy
⁷ Department of Physics and Astronomy, University of Catania, Via Santa Sofia 64, 95123 Catania, Italy
⁸ Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany

Received: 28 May 2021
Accepted: 3 December 2021

Abstract

We present a new correlation method for deriving the F-corona intensity distribution, which is based on the analysis of the evolution of the total and polarized visible light (VL) images. We studied the one-month variation profiles of the total and polarized brightness acquired with Large Angle Spectrometric COronagraph and found that in some regions they are highly correlated. Assuming that the F-corona does not vary significantly on a timescale of one month, we estimated its intensity in the high-correlation regions and reconstructed the corresponding intensity maps both during the solar-minimum and solar-maximum periods. Systematic uncertainties were estimated by performing dedicated simulations. We compared the resulting F-corona images with those determined using the inversion technique and found that the correlation method provides a smoother intensity distribution. We also obtained that the F-corona images calculated for consecutive months show no significant variation. Finally, we note that this method can be applied to the future high-cadence VL observations carried out with the Metis/Solar Orbiter coronagraph.