| Astrophysics (Index) | About |
Xenon (Xe) is the element with atomic number 54, symbol Xe. A number of its isotopes are common and stable, with mass numbers 125, 128 through 132, and 134. Additionally, 124 and 136 have very long half-lives (many gigayears, but they are still measurably radioactive in a parcel of gas that has either in substantial numbers). Xenon's abundance is low, on the order of one part per million in the solar system. It is a noble gas (aka inert gas), one of six elements with such an atomic number that an atom of the element is very unlikely to bind with another atom, i.e., it tends not to occur in compounds, and tends to be an atomic gas except at very low temperatures.
Its nuclei are synthesized by the r-process within supernovae, and by the s-process within AGB stars. It is also produced in fission.
Some xenon isotopes are used as a scintillator in a number of physics experiments including some attempting to detect WIMPs or neutrinoless double beta decay. Xenon is also a favored propellant in ion engines.