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.
Prominence dynamics
Credit: IRIS, LMSAL/NASA, Paola Testa
This IRIS movie, taken on April 4th 2016 at the solar limb, shows interesting dynamics of a "prominence" (cool gas at coronal heights). The prominence can be seen above the limb in the two movies showing the IRIS slit-jaw images (SJI) using two different filters: one, in the far ultraviolet, centered around 1400A (center panel), and one, in the near ultraviolet, centered around 2796A (right panel). These two SJI movies show how different the emission of the prominence material is at different wavelengths. IRIS also obtains spectra in the slit region clearly seen as a vertical stripe in the right panel movie. The time series of the IRIS spectra in the spectral region including Mg II emission line around 2796A is shown in the left panel of the movie. The movie of the spectra shows the dynamics of the prominence material, and its variability at different positions across the prominence. The spectra also allow us to diagnose the velocity of the emitting material, and so to reveal the presence of counterflows at the southern end of the prominence.