Total solar eclipses continue to provide unique opportunities for observing the corona, due primarily to the exceptional diagnostic capabilities offered by emission from forbidden lines. Such observations span the heliocentric distance range of 1 - 3 solar radii, providing information that is currently inaccessible to any space-borne or ground-based observatory. Taking advantage of such an opportunity, the most ambitious multi-wavelength observations to date were made simultaneously in broadband white light, H alpha 656.3 nm, Fe IX 435.9 nm, Fe X 637.4 nm, Fe XI 789.2 nm, Fe XIII 1074.7 nm, Fe XIV 530.3 nm and Ni XV 670.2 nm, during the total solar eclipse of 11 July 2010 from Tatakoto, an atoll in French Polynesia. A number of curious coronal structures, namely ripples, streaks and a structure in the shape of a hook, were detected in the images. The ripples were most prominent in emission from spectral lines associated with temperatures around 106 K. The most prominent streak was associated with a conical-shaped void in the emission from the coolest line of Fe IX and from the hottest line of Ni XV. A prominence, which erupted prior to totality, produced the hook in the cooler lines of Fe X and Fe XI, spanning 0.5 Rs in extent, centered at 1.3 Rs, with a complex trail of hot and cool twisted structures connecting it to the solar surface. These observations show for the first time how the passage of CMEs and eruptive prominences through the corona leave complex density trails with distinct temperatures.
|Cyhoeddwyd - 01 Mai 2011