A Comparison of the Red and Green Coronal Line Intensities at the 29 March 2006 and the 1 August 2008 Total Solar Eclipses: Considerations of the Temperature of the Solar Corona

TL;DR

This study compares coronal line intensities during two solar eclipses to infer changes in the solar corona's temperature, revealing a decrease in high-ionization line strength after a solar minimum.

Contribution

It provides a spectroscopic comparison of coronal emission lines at two eclipses, linking line intensity variations to coronal temperature changes.

Findings

[Fe XIV] line was weaker in 2008, indicating lower coronal temperature.

The duration of totality and flash spectrum were precisely measured.

Results suggest a cooling of the solar corona after solar minimum.

Abstract

During the total solar eclipse at Akademgorodok, Siberia, Russia, in 1 August 2008, we imaged the flash spectrum with a slitless spectrograph. We have spectroscopically determined the duration of totality, the epoch of the 2nd and 3rd contacts and the duration of the flash spectrum (63 s during ingress and 48 s during egress). Here we compare the 2008 flash spectra with those that we similarly obtained from the total solar eclipse of 29 March 2006, at Kastellorizo, Greece. Any changes of the intensity of the corona emission lines, in particularly those of [Fe X] and [Fe XIV], could give us valuable information about the energy content of the solar corona and the temperature distribution of the corona. The results show that the high-ionization state, the [Fe XIV] emission line, was much weaker during the 2008 eclipse, indicating that following the long, inactive period during the solar minimum, there was a drop in the overall temperature of the solar corona.