Detection of the lower boundary of stellar convective envelopes from seismic data

J. Christensen-Dalsgaard1, Mário J.P.F.G. Monteiro2 and Michael J. Thompson3

1 Teoretisk Astrofysik Center, Danmarks Grundforskningsfond,
and Institut for Fysik og Astronomi, Aarhus Universitet, DK-8000 Aarhus C, Denmark
2 Departamento de Matemática Aplicada, Faculdade de Ciências da Universidade do Porto,
and Centro de Astrofísica da Universidade do Porto, Rua do Campo Alegre 823, P-4150 Porto, Portugal
3 Astronomy Unit, School of Mathematical Sciences, Queen Mary & Westfield College, Mile End Road, London E1 4NS, England


The seismic study of the base of the convection zone in the Sun (eg Christensen-Dalsgaard et.al. 1995, MNRAS 276, 283) has been successful in determining not only the position of the base of the convective envelope, but also the characteristics of this transition layer. In this work we extend the analysis to other solar-type stars, possessing also convective envelopes, in order to investigate methods for determining characteristics of the envelopes of these stars. In particular, we may hope to establish seismologically that a star does indeed possess a convective envelope and to measure the size of this convective region. The method used consists in identifying a signal in the observed frequencies whose characteristics depend on the location of the base of the convective region in the star. The limitations in terms of observational uncertainties and stellar characteristics are discussed.


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