Thermal Properties of Coronal Cavities

We have analyzed 33 cavities observed between 2012 and 2018, from solar activity maximum to minimum. For each cavity we applied a differential emission measure method to obtain both a temperature distribution and a value of the average temperature. We find that cavities are filled with material hotter than the surrounding streamer, with temperatures in the range of 1.67 - 2.15 MK. Differences between temperatures of cavities and surrounding streamers are in the range of 0.11 - 0.32 MK with an average value of 0.21 MK. We found that temperatures of both, cavities and streamers, vary as a function of different phases of solar activity. During solar maximum the structures are slightly hotter than those observed during solar minimum (1.85 - 2.15 MK vs. 1.67 - 1.88 MK for cavities and streamers, respectively).