This element was discovered in 1863 in Freiberg, Germany, by F. Reich and H. Richter. The name was chosen because in the spectrum of this element there appears a bright line of indigo color.
InI 5.8 eV, InII 18.9 eV, InIII 28.0 eV.
Absorption lines of InI
The equivalent width of InI 4511(M.1 resonance line) in the sun is 0.004 (Lambert et al. 1969). The In lines are stronger in sunspot spectra. The element is also present in M 2 III stars (Davis 1947).
Emission lines of InI
InI 4511 appears in emission in long-period variables around maximum light (Merrill 1952,Joy 1954, Deutsch and Merrill 1959).
Behaviorin non-normal stars
Cowley et al. (1974) found InII lines in the spectrum of one Ap star of the Cr-Eu-Sr subgroup.
In is enhanced in at least one Ba star (Lambert 1985).
In occurs in two stable forms, In113 and In115. There exist also 32 short-lived isotopes and isomers. In the solar system the frequency of In113 is 4% and that of is In115 96%.
In113 is produced by the r, the s or the p process. In115 is only produced by the r process or the s process.
Published in "The Behavior of Chemical Elements in Stars", Carlos Jaschek and Mercedes Jaschek, 1995, Cambridge University Press.