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Space Science & Astrobiology Division Special Seminar

Title: From Dynamos to Transits: Stellar Activity in an Exoplanet Context — Speaker: Mark Giampapa
National Solar Observatory — Abstract:

The dynamo generation of magnetic fields in the Sun and stars leads to a vast array of phenomena that span an enormous range of time scales from flare outbursts—the most violent explosions in our solar system—to decadal-long modulations of the number of spots—the strongest concentrations of magnetic flux in the photosphere of the Sun and that of late-type stars.   In addition to coronal heating and transient phenomena, emergent magnetic fields modulate the luminous output and govern the angular momentum evolution of late-type stars that also leads to an additional diagnostic of stellar age.  Recent investigations, particularly involving HST and in preparation for JWST observations, have highlighted the potential influence of stellar surface heterogeneity on the interpretation of exoplanet atmospheric transmission spectra.  Exoplanet transits, in turn, can be utilized as novel probes of the properties of stellar magnetic active regions.  Results from our work in progress relevant to these topics as based on Kepler/K2 light curve analysis, NN-EXPLORE program data and near-infrared spectroscopic observations will be presented.

These investigations are supported in part by the NASA Kepler/K2 Guest Observer program and the joint NASA-NSF NN-EXPLORE program, which is administered by the NASA Exoplanet Science Institute (NExScI).  The National Solar Observatory is operated by AURA under a cooperative agreement with the National Science Foundation.

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