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Title:
Material motions in sunspot umbrae
Authors:
Beckers, J. M.
Affiliation:
AA(Sacramento Peak Observatory, Sunspot, N. Mex.)
Publication:
Astrophysical Journal, Part 1, vol. 213, May 1, 1977, p. 900-905. (ApJ Homepage)
Publication Date:
05/1977
Category:
Solar Physics
Origin:
STI
NASA/STI Keywords:
SOLAR GRAVITATION, SOLAR ROTATION, SUNSPOTS, UMBRAS, CONVECTIVE FLOW, DOPPLER EFFECT, RADIANT FLUX DENSITY, RED SHIFT, SOLAR LIMB, SOLAR SPECTRA
Comment:
A&AA ID. AAA019.072.012
DOI:
10.1086/155222
Bibliographic Code:
1977ApJ...213..900B

Abstract

Material motions in the umbrae of a number of sunspots have been measured on an absolute scale by means of the g = 0 line of Ti I at 5713 A. It is found that the rates of solar rotation as derived from sunspot proper motions and from spectra are identical to within 1% and that the vertical flow inside umbrae is small, being less than 25 m/s when the pressure shift is ignored. The so-called limb effect is absent in the umbrae leading to an upper limit to the convective energy flux of 0.5% of the radiative energy flux outside sunspots. The position of the line with respect to its laboratory wavelengths is shifted to the red by 613 m/s, in agreement with the predicted gravitational redshift of 636 m/s.

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