Radiative emission of solar features in Ca II K

TL;DR

This study analyzes the radiative emission of various solar features in the Ca II K line using high-resolution observations and compares the results with radiative transfer models to understand solar chromospheric activity.

Contribution

It provides a detailed comparison of observed solar feature emissions in Ca II K with numerical synthesis based on semi-empirical models, enhancing understanding of solar chromospheric diagnostics.

Findings

Quantified intensity and contrast of different solar features in Ca II K

Compared observational data with radiative transfer simulations

Improved understanding of solar chromospheric emission mechanisms

Abstract

We investigated the radiative emission of different types of solar features in the spectral range of the Ca II K line. We analyzed full-disk 2k x 2k observations from the PSPT Precision Solar Photometric Telescope. The data were obtained by using three narrow-band interference filters that sample the Ca II K line with different pass bands. Two filters are centered in the line core, the other in the red wing of the line. We measured the intensity and contrast of various solar features, specifically quiet Sun (inter-network), network, enhanced network, plage, and bright plage (facula) regions. Moreover, we compared the results obtained with those derived from the numerical synthesis performed for the three PSPT filters with a widely used radiative code on a set of reference semi-empirical atmosphere models.