HR: 0830h
AN: SP11B-10    [Abstracts]
TI: The structure of the near-surface layers of the Sun: asphericity and time variation
AU: * Basu, S
EM: basu@astro.yale.edu
AF: Yale University, P.O. Box 208101, New Haven, CT 06520-8101 United States
AU: Bogart, R S
EM: RBogart@spd.aas.org
AF: Stanford University, HEPL Annex, Stanford, CA 94305-4085 United States
AU: Antia, H M
EM: antia@tifr.res.in
AF: Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, 400 005 India
AB: We present results on the structure of the near-surface layers of the Sun. These results were obtained by inverting frequencies of high-degree solar modes obtained by using "ring diagrams". We have results for seven epochs from June 1996 to March 2002. The frequencies of each epoch were obtained from ring diagrams constructed from MDI Dopplergrams spanning one complete Carrington rotation. We find that there is a substantial latitudinal variation of both sound speed and the adiabatic index Γ₁ in the outer 2% of the Sun. In addition, it appears that both the sound-speed and Γ₁ profiles change with change in the level of solar activity.
DE: 7522 Helioseismology
DE: 7536 Solar activity cycle (2162)
DE: 7544 Stellar interiors and dynamo theory
SC: Solar Physics Division - AAS [SP]
MN: 2005 Joint Assembly