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Akademie věd České republiky |
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Akademie věd České republiky |
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Mimořádný seminář 12. 11. 2004
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který se koná v pátek 12. listopadu 2004, 10:00 v zasedací místnosti Kosmické laboratoře v OndřejověPROGRAM: Sunspots, Gravitational
Redshifts and Exo-Solar Planet Search (National Optical Astronomy Observatory, USA) I revisit a paper I wrote in 1977 on the spectral line shifts in sunspot umbra observed on an absolute wavelength scale. In that paper I examined not only the motions inside sunspots but also the then already known issues associated with the "Limb Effect" in the spectrum of the quiet photosphere (observed in 1907 by Halm). These issues include what is now known as the "convective blueshift" and the Einstein gravitational redshift. In sunspots things behave quite differently. In my talk I will compare sunspot and quiet photosphere spectral line shifts from the modern day perspective. Although recent modeling of solar surface convection has resulted in an unambiguous interpretation of the quiet photosphere line profile and shift observations, the 1977 paper appears to report the only work done on the topic in sunspots, both covering observations and interpretation. The observational technique developed for that research has led directly to one of the two techniques used by many exosolar "planet hunters". Srdečně zvou František Fárník Miroslav Bárta |