An Etymological Dictionary of Astronomy and Astrophysics

A colorless, odorless, tasteless, chemically un-reactive gas, belonging to the → inert gas group, occurring in exceedingly minute amounts in the air; symbol Xe. → Atomic number 54; → atomic weight 131.29; → melting point -111.9°C; → boiling point -107.1°C. Xenon was discovered spectroscopically in 1898 by William Ramsay and M. W. Travers, who obtained it by fractional distillation of an impure sample of liquid → krypton.

The lightest → isotopes of xenon (¹²⁴Xe and ¹²⁶Xe) are produced during → supernova explosions; intermediate-mass isotopes (¹²⁷Xe, ¹²⁸Xe, ¹²⁹Xe, ¹³⁰Xe, ¹³¹Xe and ¹³²Xe) are produced during the → Asymptotic Giant Branch phase of evolved low- and intermediate-mass stars; the heaviest isotopes (¹³⁴Xe and ¹³⁶Xe) are produced during the → merger of → neutron stars.

See also: From Gk. xenon, neuter of xenos “strange,” introduced by the discoverers.