This element was discovered by S. Tennant in London in 1803. The name comes from the Latin iris (rainbow), because iridium salts are highly colored.
IrI 9.1 eV, IrII 17.4 eV.
Absorption lines of IrI
In the sun, IrI 3221(5) has W = 0.032.
Behavior in non-normal stars
IrI was reported in one Ap star of the Cr-Eu-Sr group by Guthrie (1972).
Ir occurs in two stable forms, Ir191 and Ir193. In the solar system Ir191 represents 37% and Ir193, 63% of total iodine. There exist also 23 short-lived isotopes and isomers.
Both isotopes are only produced by the r process.
Published in "The Behavior of Chemical Elements in Stars", Carlos Jaschek and Mercedes Jaschek, 1995, Cambridge University Press.