The quantum interference effects in the Sc II 4247 A line of the Second Solar Spectrum

TL;DR

This study investigates the quantum interference effects in the Sc II 4247 A line of the solar spectrum, revealing that current models cannot fully reproduce the observed triple peak structure, suggesting missing quantum physics elements.

Contribution

The paper applies F-state interference theory with PRD and RT effects to model the line, highlighting limitations in current 1D and multi-component models in reproducing the central peak.

Findings

PRD and RT effects reproduce wing peaks but not the central peak.

Hyperfine structure causes depolarization suppressing the central peak.

Multidimensional models do not resolve the central peak discrepancy.

Abstract

The Sc II 4247 A line formed in the chromosphere is one of the lines well known, like the Na I D_2 and Ba II D_2, for its prominent triple peak structure in Q/I and the underlying quantum interference effects governing it. In this paper, we try to study the nature of this triple peak structure using the theory of F-state interference including the effects of partial frequency redistribution (PRD) and radiative transfer (RT). We compare our results with the observations taken in a quiet region near the solar limb. In spite of accounting for PRD and RT effects it has not been possible to reproduce the observed triple peak structure in Q/I. While the two wing PRD peaks (on either side of central peak) and the near wing continuum can be reproduced, the central peak is completely suppressed by the enhanced depolarization resulting from the hyperfine structure splitting. This suppression remains for all the tested widely different 1D model atmospheres or for any multi-component combinations of them. While multidimensional radiative transfer effects may improve the fit to the intensity profiles, they do not appear capable of explaining the enigmatic central Q/I peak. This leads us to suspect that some aspect of quantum physics is missing.