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D. M. Rabin (NSO/NOAO), T. A. Clark, M. W. Bergman (University of Calgary)
We report preliminary results from a program to map the concentration of H2O, OH, and SiO in the atmospheres of sunspots using imaging infrared spectroscopy. The water molecule is confined to the inner core of the umbra, whereas OH can sometimes be detected in the penumbra. Plots of line depth against continuum intensity show an abrupt onset of absorption at a different intensity for each molecule. A larger sample is needed to decide to what extent such features are characteristic. Evershed flow is seen in OH in the penumbra of spots near the limb, with typical outward velocities of 1-2 km s-1. Spatial imaging of molecular concentrations in sunspots should eventually provide new diagnostics for the temperature structure of the umbral atmosphere, as yet poorly determined.
This work has been supported by the University of Calgary and by the National Science Foundation through its support of NSO/NOAO.