Seismic investigations of the sun and solar-like stars

[摘要] The first study in this thesis presents a method for identifying the angular degree in stars where only two ridges are seen when plotted on an echelle diagram. Three methods are discussed which use comparison techniques in an attempt to obtain an identification for a newly observed star to one where the identity of the degree is already known. The first two require prior knowledge of the radial order of a mode. The third replaces the radial order with a reduced frequency. When tested on 1005 model pairs of stars this last method successfully identifies the angular degree in 1003 cases or 99.8%. The second study investigates changes with the Sun that could cause or be caused by the most recent extended solar minimum. We have compared data collected from the Birmingham Solar-Oscillation Network during the minima of three solar cycles. Frequency differences are created between modes of oscillation observed by BiSON in the most recent minima and the two before. The type of oscillatory frequency shift seen in the data suggests a sharp change has occurred in \(\Gamma\)\(_1\) at a depth within the Sun of 0.015 solar radii.

[发布机构] University:University of Birmingham;Department:School of Physics and Astronomy

[关键词] Q Science;QB Astronomy