EDP Sciences
Free access
Volume 395, Number 1, November III 2002
Page(s) 279 - 284
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20021239

A&A 395, 279-284 (2002)
DOI: 10.1051/0004-6361:20021239

Formation of granular intensity fluctuations on the Sun

E. Pérez Rodríguez and F. Kneer

Universitäts-Sternwarte, Geismarlandstraße 11, 37083 Göttingen, Germany

(Received 24 June 2002 / Accepted 27 August 2002 )

We deal with granular intensity fluctuations in the Sun and how they are caused by temperature fluctuations. We calculate temperature response functions $RF_{\rm T}(\lambda,z)$ in the solar photosphere. We apply the Diagonal Element Lambda Operator (DELO) method to calculate the response functions for the continuum ( $\lambda\lambda = 380$ nm-2.5 $\mu$). LTE is assumed throughout. It is demonstrated that, within the framework of the linear approximation, the H - continuum absorption plays an important rôle for the formation of the fluctuations in continuum images. It counteracts substantially the intensity fluctuations caused by variations of the Planck function. The temperature response functions are used to calculate, for three models of temperature fluctuations, the continuum intensity contrasts and their formation height for the above wavelength range.

Key words: Sun: photosphere -- Sun: granulation -- radiative transfer

Offprint request: F. Kneer, kneer@uni-sw.gwdg.de

© ESO 2002