Asteroseismology

The asteroseismology ( asteroseismology ) tries to tap into their inner structure of the observed oscillations in the brightness or velocity of stars. At the very successful application to the sun is called helioseismology.

Although the name suggests otherwise, asteroseismology is not based on ' star quakes ', but on the observation of constantly occurring oscillations. Similar to a swinging bell this resonance frequencies depend on mass and structure of the star. Your exact measurement can thus provide information about the structure of deeper, otherwise not directly observable layers of a star.

It should be noted that it should actually be called asteroseismology, with correct derivation of the name from the Greek. However, asteroseismology has naturalized as a result of a failure of a well-known astronomer, since this includes the Subject negligent in its publications manner has so designated.

Methods

The brightness fluctuations are usually so small that their detection in other normal stars than the sun never really convincingly achieved from the ground because of atmospheric turbulence. Therefore, the hopes are based on brightness measurements from the much more stable viewing position of satellites in space (see WIRE, MOST, COROT, Kepler ). The stronger brightness fluctuations of pulsating variable stars could, however, be measured from ground-based observatories already.

From Earth, spectroscopic methods are applied. It searches in the spectra of stars to red - or blue-shifted spectral lines show a change in the radial velocity. This method is mainly used for the detection of extrasolar planets, as these by gravitational disturbances a periodic variation of the radial velocity cause ( radial velocity method ). It can thus be investigated and the faster, the internal vibrations of the star.