An Asteroseismological Analysis of the Short-Period Pulsating sdB Star EC 05217-3914

摘要

We present the results of a detailed asteroseimological analysisof the southern hemisphere sdB pulsator EC 05217-3914. This analysis restson our gathering of high S/N ratio observations at the NTT using the SUSI2camera. Some 37 h of data were obtained over a 5 night run. We uncoveredseveral frequency components in the period range 129-218 s, several of whichform multiplets with equally spaced components. The latter are best explained interms of rotational splitting in a star with a rotation period of 13.1 h. Excludingthe rotationally-split components, we identified 5 independent pulsation modeswith which to play the game of asteroseismology. Using an efficient period-matching code we explored the parameter space and found an excellent fit tothe observed periods. We present the results of this exercise: our preliminaryidentification of the pulsation modes in EC 05217-3914 and the determinationof its fundamental parameters through asteroseismology.