Small separations and phase shift differences of = 0, 1 p-modes
Astronomy Unit, Queen Mary, University of London, Mile End Road, London E1 4NS, UK e-mail: I.W.Roxburgh@qmul.ac.uk
2 LESIA, Observatoire de Paris, Place Jules Janssen, 92195 Meudon, France
Accepted: 26 October 2008
Aims. We investigate the diagnostic potential of = 0,1 p-modes and the origin of the periodicity in their small separations.
Methods. We used theoretical analysis, phase-shifts, modelling. and data analysis.
Results. The periodicity in the small separations between modes of = 0, 1 is determined by the acoustic radius of the base of the outer convective envelope. The mean variation is determined primarily by the structure of the inner core. The separations are related to the inner phase shifts differences which we show can be determined directly from the frequencies. The modulation period is shifted slightly by the frequency dependence of the phase shifts and the amplitudes. We present results using data from the BiSON, IRIS, and GOLF experiments, and a solar model, all of which give a modulation period of ~359±5 μHz corresponding to an acoustic radius ~1422±20 s.
Key words: stars: oscillations / stars: interiors
© ESO, 2008