Plutonium was discovered by a team led by Glenn T. Seaborg, Joseph W. Kennedy, Edward M. McMillan, and Arthur C. Wahl (Wohl) at the University of California, Berkeley, in late 1940 to early 1941 through deuteron bombardment of uranium-238 in a cyclotron, producing neptunium-238 which beta-decayed to plutonium-238, with plutonium-239 identified soon after and its fission properties studied in 1941–1942.

Key details:

• Discovery team: Glenn T. Seaborg, Joseph W. Kennedy, Edward M. McMillan, and Arthur C. Wahl (Wohl).

• Method: Bombardment of uranium-238 with deuterons in a cyclotron, yielding neptunium-238 which decays to plutonium-238; later identification of plutonium-239 and confirmation of fissionability.

• Timing: Production in 1940–1941; public disclosure and broader recognition in 1946 due to wartime security concerns.

• Nomenclature: Named "plutonium" after the planet Pluto, following the earlier naming of neptunium after Neptune.

• Notable isotopes: Pu-239 (longer-lived, key for weapons research) and Pu-238 (used in space power sources and other devices).

If you’d like, I can pull concise biographical notes on each discoverer or provide a brief timeline with exact dates and publications.