This element was discovered by C. Mosander in Stockholm in 1843. Its name comes from Ytterby in Sweden.
TbI 5.8 eV, TbII 11.5 eV, TbIII 21.9 eV.
Behavior in stars
Tb lines have not been definitely identified in the sun. Reynolds et al. (1988) observed Tb in one F0Ib star (W(3874) = 0.004) and Davis (1947) observed Tb in one M2III object.
TbII (3874, 3899, 4144) is seen in some Ap stars of the Cr-Eu-Sr subgroup (Adelman 1973b, Cowley and Henry 1979, Adelman et al. 1979) and in at least one late Am star, where W(4144) = 0.054 (van 't Veer-Menneret et al. 1988).
Tb has one stable isotope, Tb159, and 23 short-lived isotopes and isomers.
Tb can only be produced by the r process.
Published in "The Behavior of Chemical Elements in Stars", Carlos Jaschek and Mercedes Jaschek, 1995, Cambridge University Press.