TY  - JOUR
A1  - Diercke, Andrea
A1  - Denker, Carsten
T1  - Chromospheric Synoptic Maps of Polar Crown Filaments
JF  - Solar physics : a journal for solar and solar-stellar research and the study of solar terrestrial physics
N2  - Polar crown filaments form above the polarity inversion line between the old magnetic flux of the previous cycle and the new magnetic flux of the current cycle. Studying their appearance and their properties can lead to a better understanding of the solar cycle. We use full-disk data of the Chromospheric Telescope (ChroTel) at the Observatorio del Teide, Tenerife, Spain, which were taken in three different chromospheric absorption lines (H alpha lambda 6563 angstrom, Ca II K lambda 3933 angstrom, and He I lambda 10830 angstrom), and we create synoptic maps. In addition, the spectroscopic He I data allow us to compute Doppler velocities and to create synoptic Doppler maps. ChroTel data cover the rising and decaying phase of Solar Cycle 24 on about 1000 days between 2012 and 2018. Based on these data, we automatically extract polar crown filaments with image-processing tools and study their properties. We compare contrast maps of polar crown filaments with those of quiet-Sun filaments. Furthermore, we present a super-synoptic map summarizing the entire ChroTel database. In summary, we provide statistical properties, i.e. number and location of filaments, area, and tilt angle for both the maximum and the declining phase of Solar Cycle 24. This demonstrates that ChroTel provides a promising data set to study the solar cycle.
KW  - Chromosphere, quiet
KW  - Prominences, quiescent
KW  - Prominences, magnetic field
KW  - Solar Cycle, observations
KW  - Instrumentation and data management
Y1  - 0201
U6  - https://doi.org/10.1007/s11207-019-1538-z
SN  - 0038-0938
SN  - 1573-093X
VL  - 294
IS  - 11
PB  - Springer
CY  - Dordrecht
ER  -