XTE will provide new astrophysical data on exotic objects such as accreting black holes, active galactic nuclei, jets and relativistic beams, pulsar beaming, and X-ray bursts. If the two stars are close enough, material from the normal star will flow onto the compact star attracted by gravity. As the gas falls down the steep gravitational well of the compact star its temperature rises to the point where X-rays are emitted. These X-rays provide detailed information about the conditions in the region of the extremely strong gravitational field and magnetic fields near the compact object. Variations in intensity are a typical characteristic of emission of compact sources and provide crucial information about the dimensions of such sources.
Spectral information provides diagnostics of the underlying emission processes.
For the first time, studies of X-ray variability ranging from microseconds to several years will be carried out.