Vanden Broeck, Grégory ; Bechet, Sabrina ; Rauw, Grégor

Poster presented at International Astronomical Union General Assembly 2024 - Cape Town, South Africa on 2024-08-13

Abstract: The chromospheric emission in the Ca II K line is a primary tracer of the magnetic activity of the Sun and other Sun-like stars. The Sun is observed from Earth from its Equator's point of view, whereas other stars are observed at all possible viewing angles. 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 disk-resolved indices such as the plage area and intensity. These indices are strongly correlated to the S-index, a well-known index to study the magnetic activity of stars, and could help to better understand the magnetic activity of Sun-like stars. We have studied the effect of the inclination rotation axis on disk-resolved indices using the archives of synoptic full-disk images taken on site at the Royal Observatory of Belgium with the Uccle Solar Equatorial Table (USET) since 2012.

Keyword(s): Sun: activity ; Sun: chromosphere ; Sun: faculae, plages ; stars: activity ; stars: solar-type
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