000006964 001__ 6964
000006964 005__ 20240415135524.0
000006964 037__ $$aCTALK-2024-0113
000006964 100__ $$aVanden Broeck, Grégory
000006964 245__ $$aEffect of the inclination angle of solar rotation axis on Ca II K structures using direct solar observations
000006964 260__ $$c2024
000006964 269__ $$c2024-04-09
000006964 520__ $$aThe chromospheric emission in the Ca II K line is a primary tracer of magnetic activity in the Sun and other Sun-like stars. Our goal is to study the long-term brightness variation of the chromosphere in this line taking into account the different chromospheric structures. The Sun is observed from Earth from its Equator's point of view, whereas others stars are observed at all possible inclinations. The chromospheric plages, main contributors to the Ca II K emission, are distributed between mid-latitude and the Equator. Therefore, we suspect that the inclination angle of the solar rotation axis has an impact on the observed plages area fraction and intensity. Until now, the effect of such inclination on Ca II K plages areas has not been extensively studied through direct solar observations. For this study, we exploit the archives of synoptic full-disc images taken on-site at the Royal Observatory of Belgium with the Uccle Solar Equatorial Table (USET) since 2012. We first describe the methods to estimate the bright plages area fraction from the USET images. Then we explain how we reconstruct the solar images for multiple inclinations. Finally, we show the results obtained for the dependance of the inclination angle of view on the Ca II K plages area.
000006964 594__ $$aNO
000006964 6531_ $$aSun: activity
000006964 6531_ $$aSun: chromosphere
000006964 6531_ $$aSun: plages
000006964 6531_ $$aSun: Sun-as-a-star
000006964 6531_ $$aSun: rotation period
000006964 700__ $$aBechet, Sabrina
000006964 700__ $$aRauw, Gregor
000006964 700__ $$aClette, Frédéric
000006964 773__ $$tTriennial Earth-Sun Summit, Dallas, United States
000006964 8560_ $$fgregory.vandenbroeck@ksb-orb.be
000006964 8564_ $$s15056295$$uhttp://publi2-as.oma.be/record/6964/files/TESS24_VandenBroeck_ID11406.pptx$$yPowerpoint of the oral presentation
000006964 906__ $$aContributed
000006964 980__ $$aCTALKCONT