Göttingen 2025 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 10: Poster Session
EP 10.17: Poster
Thursday, April 3, 2025, 11:00–12:30, ZHG Foyer 1. OG
Chromospheric Fe I lines in the NUV solar spectrum — •Edvarda Harnes1,2, Smitha Narayanamurthy1, Andreas Korpi-Lagg1,3, Damien Przybylski1, and Sami Solanki1 — 1Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany — 2Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 3Aalto University, Department of Computer Science, Konemiehentie 2, 02150 Espoo, Finland
In the near-ultraviolet (NUV) solar spectrum there are several Fe I lines that show very broad profiles typical of chromospheric lines. The diagnostic potential of these spectral lines is largely unexplored due to a lack of high-resolution observations. With the successful flight of the SUNRISE III balloon-borne observatory we have for the first time full spectro-polarimetric data at high spatial resolution of this region, and ground-based observatories can also observe the broad Fe I lines around 400 nm. The goal of this work is to investigate and discuss the formation properties of these spectral lines and their suitability for interpreting observations. An initial investigation was done by synthesizing a selection of lines in the FAL one-dimensional semi-empirical solar atmosphere models using the non-LTE radiative transfer code RH. We found that the lines are significantly affected by overionization in the wings and scattering in the chromospheric line cores. The next step is to investigate the lines in a dynamic atmosphere of a 3D radiation-MHD model, made with the chromospheric extension of MURaM, and results from this will be presented.
Keywords: Solar spectrum; Near-ultraviolet; Chromosphere; Radiative transfer