Asteroseismology from the main sequence to giant stars

The thesis focuses on the use of asteroseismology to probe the structure of stellar sources. By observing pulsational variability, a detailed description of the interior of stars, and the determination of stellar parameters can be obtained. An extensive sample of bright K and M class giant stars were surveyed to detect the presence of any noticeable variability. Three giant stars have been studied in detail. In Arcturus (alpha Boo), no oscillations at a significant amplitude were detected. In beta UMi (Kochab) multiperiodic oscillations have been observed for the first time, allowing an asteroseismic estimate for the mass. In gamma Crucis (Gacrux) previously observed frequencies have been confirmed, and the modes shown to be sinusoidal in nature. Two main-sequence stars have been studied in detail. In the first, gamma Dor, prototype star of the class of gamma Doradus variable stars, three oscillations further to those previously known were unambiguously detected in the star. In the second, nu Eri, a beta Cephei class variable star, modes detected by an extensive previous campaign were confirmed, with determined frequencies in excellent agreement between the two studies. All results gathered should provide a valuable input to future models of these stars, and provide an interesting starting point for further, detailed studies.

Name dc:type.qualificationname

d_ph

Level dc:type.qualificationlevel

d_ph

Grantor dc:publisher.institution

University of Birmingham

Year dc:date.issued

2010

Author dc:creator

• Tarrant, Neil James

• QB Astronomy