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Astron. Astrophys. 330, 359-361 (1998)

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Research Note

On velocity and intensity line asymmetries

M. Gabriel

Institut d'Astrophysique de l'Université de Liège, 5, avenue de Cointe, B-4000 Liège, Belgium

Received 7 July 1997 / Accepted 29 September 1997


We show that, if solar 5 min. oscillations are excited by convection in the upper layers of the convective envelope, it is impossible to explain the opposite line asymmetries observed in the velocity and intensity spectra with assumptions on the dissip

ations which reduce the problem to a second order one. The interpretation of that observation requires to solve the full non-adiabatic problem which is of the fourth or sixth order. We also analyze the causes of line asymmetries in the frame of the gene

ral problem and we show that to locate the source, it is better to study line asymmetries not too far from line centers.

Key words: Sun: oscillations – lines: profiles

Send offprint requests to: M. Gabriel

© European Southern Observatory (ESO) 1998

Online publication: January 8, 1998