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Астрофизический семинар ИНАСАН № 160 (20 ноября 2008 г.,11:00)

Опубликовано: 20/11/2008

Докладчик: Саванов И.С. (ИНАСАН)

Название доклада: “Doppler imaging and light-curve inversions”

Краткое содержание доклада:

One of the most challenging observational goals of today’s Doppler imaging research is to obtain two-dimensional images of inhomogeneous stellar surfaces to relate disk integrated observations to spatially resolved surface features. Chemically peculiar stars host strong global magnetic fields and show spots of chemical elements. The long-standing puzzle is the origin and geometry of magnetic fields in these stars and mechanisms of the interaction between the field and chemical spots. Spots cooler than the undisturbed photosphere of a late-type star are a manifestation of surface magnetic fields and a time-dependent study of their latitudinal and longitudinal behavior provides a direct link to the internal stellar dynamo. I would like to review history of Doppler imaging technique, its modern status and several mathematical aspects of the inverse problem solutions.

I shall present also my new inversion code that reconstructs the stellar surface spot configuration from the light curve of a rotating star. Our code employs a method that uses the truncated least-squares estimation of the inverse problem’s objects principal components. We use spot filling factors as the unknown objects. Various test cases that represent a rapidly-rotating K subgiant are used for the forward problem. The code is then applied to ten years of V and I-band light curve data of the spotted sub-giant HD 291095, active RS CVn binary HD 127535 (V841 Cen) and Corot-exo-2b object.