A&A 382, 312-318 (2002)
Center-to-limb-variation of the G-band lines at 430.5 nmK. Langhans and W. Schmidt
Kiepenheuer-Institut für Sonnenphysik, Schöneckstr. 6, 79104 Freiburg, Germany
(Received 10 September 2001 / Accepted 8 November 2001 )
We measure the center-to-limb-variation of the CH lines in the wavelength range from 430.40 to 430.61 nm (G-band) for both quiet sun and for the cooler atmophere of sunspot umbrae at different heliographic positions. The limb effect of the CH lines is about 650 ms -1 at with a slope similar to weak Fe lines. We investigate the behaviour of the CH abundance in the range of optical depth ( to ) that is accessible by center-to-limb observations. The CH abundance decreases with height in accordance with recent numerical models.
Key words: Sun: atmosphere, photosphere
Offprint request: K. Langhans, email@example.com
© ESO 2002