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Coronal and transition region observations of the sun and cool stars

Williams, David Ronan

This thesis presents observations of dynamic events in the outer atmosphere of the Sun and other cool stars. The effect of opacity on ratios of strong transition region lines is investigated for the flare dMe star YZ CMi, and the RS CVn binary Capella. Opacity is shown to be both an important effect in these stars' atmospheres and an important dia…

An Observational Study of Helium in the Solar Corona with the EIT Instrument on Board the SOHO Spacecraft

Auchere, F.

Helium is the second most abundant element in the Universe. The understanding of the physicals processes associated with helium as well as the determination of the helium abundance both have implications in various research fields such as cosmology, stellar evolution or the physics of the solar wind. Helioseismology techniques give accurate measur…