IRIS Movie of the Day
At least once a week a movie of the Sun taken by NASA's Interface Region Imaging Spectrograph (IRIS) is posted by one of the scientists operating the instrument.
One Loop, Two Loop, Hot Loop, Cool Loop
Credit: IRIS, LMSAL/NASA, Kathy Reeves
A faint, fuzzy magnetic loop appears on the limb at the beginning of this 1330 SJI movie. It fades away, and is replaced by a sharper, more well-defined loop about an hour and a half later. The first loop is a hot loop from Fe XXI (formed at 10 million degrees) emitting in the 1330 A bandpass. Later it cools down to the cooler temperatures of C II (30,000 degrees), which also emits in this bandpass. It takes more than an hour for the loop to cool from 10 million degrees to 30,000 degrees.