X-ray Burster - Observation of Bursts

Observation of Bursts

Because an enormous amount of energy is released in a short period of time, much of the energy is released as high energy photons in accordance with the theory of black body radiation, in this case X-rays. This release of energy may be observed as in increase in the star's luminosity with a space telescope, and is called an X-ray burst. These bursts cannot be observed on Earth's surface because our atmosphere is opaque to X-rays. Most X-ray bursting stars exhibit recurrent bursts because the bursts are not powerful enough to disrupt the stability or orbit of either star, and the whole process may begin again. Most X-ray bursters have irregular periods, which can be on the order of a few hours to many months, depending on factors such as the masses of the stars, the distance between the two stars, the rate of accretion, and the exact composition of the accreted material. Observationally, X-ray bursts are put into two distinct categories, labeled Type I and Type II. A Type I X-ray burst has a sharp rise followed by a slow and gradual decline of the luminosity profile. A Type II X-ray burst exhibits a quick pulse shape and may have many fast bursts separated by minutes. However, only from two sources have Type II X-ray bursts been observed, and so most X-ray bursts are assumed to be of Type I.