High-spectral Resolution, Multi-wavelength Center-to-limb Observations of the Sun

TL;DR

This study presents high-spectral resolution, multi-wavelength observations of the Sun's center-to-limb variations, providing detailed spectroheliograms and physical parameter maps useful for stellar and exoplanet atmosphere research.

Contribution

It introduces a novel multi-line, high-resolution spectroscopic dataset of the Sun's lower atmosphere, capturing CLVs across photospheric and chromospheric lines with simultaneous multi-wavelength observations.

Findings

Demonstrated diagnostic potential of high-resolution drift scans.

Produced detailed spectroheliograms and physical parameter maps.

Showcased the dataset's utility for stellar atmosphere characterization.

Abstract

The center-to-limb variations (CLVs) of photospheric and chromospheric spectral lines were obtained in 2025 July and August using drift scans from the echelle spectrograph of the 0.7 m Vacuum Tower Telescope at the Observatorio del Teide (ODT) in Tenerife, Spain. This instrument can observe four spectral regions simultaneously, enabling multi-line spectroscopy with high spectral resolution of various activity features and the quiet Sun in the lower solar atmosphere. The initial results of Halpha observations demonstrate the diagnostic potential of drift scans obtained with a ground-based, high-resolution telescope. Data products include spectroheliograms and maps of physical parameters such as line-of-sight velocity, line width, and line-core intensity. The combination of the CLV from photospheric and chromospheric lines, as well as the wide range of formation heights of the selected lines, renders this dataset ideal for characterizing stellar and exoplanet atmospheres.