This element was discovered by G. T. Seaborg, A. C. Wahl and J. W. Kennedy in 1940 in Berkeley, USA. Its name alludes to the planet Pluto. The name of Pluto corresponds to the Roman god of the underworld.
PuI 6.1 eV.
Lines of this element were reported by Jaschek and Brandi (1972) in one Ap star. No later confirmation of this identification has been made.
The longest lived isotope is Pu244 with a half life of 7.5 × 107 years (Burbidge et al. 1957) and could be used for radioactive dating.
The element is produced by the r process.
Published in "The Behavior of Chemical Elements in Stars", Carlos Jaschek and Mercedes Jaschek, 1995, Cambridge University Press.