BEGIN:VCALENDAR VERSION:2.0 PRODID:-//AIP Calendar//www.aip.de// BEGIN:VEVENT SUMMARY:Colloquium | Serena Criscuoli (National Solar Observatory | Boulde r\, CO\, USA) DTSTART:20260618T123000Z DTEND:20260618T133000Z DTSTAMP:20260602T044728Z UID:www.aip.de-2352 CATEGORIES:Wissenschaftliches CATEGORIES:Wissenschaftlicher Vortrag CATEGORIES:öffentlich CATEGORIES:Kolloquium CONTACT:Julián Alvarado-Gómez DESCRIPTION:Speaker: Serena Criscuoli (National Solar Observatory | Boulde r\, CO\, USA)\nTitle: Using Spatially Resolved Solar Observations to Impro ve Models of Solar and Stellar Variability\nAbstract: Models of solar and stellar variability are essential for a wide range of applications\, from understanding the influence of solar irradiance on Earth's atmosphere to c haracterizing exoplanet host stars and improving the detectability of exop lanets. Over the past decades\, irradiance variability models have achieve d considerable success in reproducing many observed signatures of magnetic activity. However\, important discrepancies remain\, highlighting limitat ions in our understanding of how different atmospheric structures contribu te to spectral variability.\nIn this seminar\, I will provide a brief over view of current solar and stellar variability models\, discussing both the ir achievements and their outstanding challenges. I will then focus on one puzzling problem: the variability of the hydrogen Balmer lines. These lin es\, especially Hα\, Hβ\, Hγ\, and Hδ\, are among the most widely used diagnostics of stellar magnetic activity\, yet recent observations have r evealed complex and sometimes unexpected behavior\, including weak or even anti-correlated variations with traditional chromospheric activity indica tors such as the Ca II lines.\nI will present recent efforts to understand the origin of this behavior through a combination of disk-integrated obse rvations\, spatially resolved measurements\, and semi-empirical atmospheri c modeling. I will discuss how modern high-resolution observations enable us to identify the physical origins of these discrepancies and refine exis ting models. Particular attention will be given to recent observations acq uired with the IAG spectrograph and results from the Visible Spectro-Polar imeter (ViSP) at the Daniel K. Inouye Solar Telescope\, which provide new insights into the relationship between magnetic activity and Balmer-line v ariability in the Sun and solar-like stars. Finally\, I will present preli minary results from an analysis of synoptic ChroTel Hα and Ca II K observ ations\, which suggest that chromospheric features\, often neglected in cu rrent solar and stellar irradiance models\, may play a role in shaping chr omospheric variability\nNote: Host: Meetu Verma\n LOCATION:AIP\; Kirch-Haus\, Konferenzraum END:VEVENT END:VCALENDAR