The Solar Limb Effect: Observations of Line Contours and Line Shifts
نویسندگان
چکیده
منابع مشابه
Stellar Surface Convection, Line Asymmetries, and Wavelength Shifts 1. Solar Line Asymmetries and Shifts
Wavelength positions of photospheric absorption lines may be aaected by surface convection (stellar granulation). Asymmetries and wavelength shifts originate from correlated velocity and brightness patterns: rising (blueshifted) elements are hot (bright), and convective blueshifts result from a larger contribution of such blueshifted photons than of redshifted ones from the sinking and cooler (...
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Most of the contour detection methods suffers from some drawbacks such as noise, occlusion of objects, shifting, scaling and rotation of objects in image which they suppress the recognition accuracy. To solve the problem, this paper utilizes Zernike Moment (ZM) and Pseudo Zernike Moment (PZM) to extract object contour features in all situations such as rotation, scaling and shifting of object i...
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Full disk images from SUMER/SoHO taken in He i, C iv and Ne viii are used to investigate whether there exists a center-to-limb variation in the line width. Both C iv and He i show such a variation but the higher temperature Ne viii line is relatively constant. For C iv, this corresponds to ∼ 3 km s−1 difference while He i is significantly larger particularly at the limb. This work may suggest t...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1976
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/177.3.687