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arXiv · 1002.4381

HST Spectrophotometry and Models for Solar Analogs

R. C. Bohlin
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Abstract

Absolute flux distributions for seven solar analog stars are measured from 0.3 to 2.5 μm by HST spectrophotometry.In order to predict the longer wavelength mid-IR fluxes that are required for JWST calibration, the HST SEDs are fit with Castelli & Kurucz model atmospheres; and the results are compared with fits from the MARCS model grid. The rms residuals in 10 broad band bins are all <0.5% for the best fits from both model grids. However, the fits differ systematically: The MARCS fits are 40-100 K hotter in T_{eff}, 0.25-0.80 higher in log g, 0.01-0.10 higher in log z, and 0.008-0.021 higher in the reddening E(B-V), probably because their specifications include different metal abundances. Despite these differences in the parameters of the fits, the predicted mid-IR fluxes differ by only ~1%; and the modeled flux distributions of these G stars have an estimated ensemble accuracy of 2% out to 30 μm.

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R. C. Bohlin. 2010-02-23. HST Spectrophotometry and Models for Solar Analogs. https://doi.org/10.1088/0004-6256%2F139%2F4%2F1515

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