Speaker
Description
We describe transient brightenings in a very quiet Sun region detected with SUNRISE III/SUSI spectroscopic observations covering the Ca II K at 3933.663 Angstrom. The Ca II K line is one of the strongest lines in the solar spectrum and serves as a key diagnostic of the solar atmosphere. On its wings there are plenty of absorption lines that originate from various atmospheric heights. At some locations in the QS region, some of these lines exhibit Line Excesses (LEs), with several of them even appearing in emission. All of them are accompanied by Ca II K wing enhancements while only part of them are also associated with Ca II K core brightenings. These LEs show red/blue asymmetries, providing evidence for energy and mass flows in the solar lower atmosphere. In addition, we find that this type of brightenings is ubiquitous in the QS, even in the seemingly quietest regions.