lines which are present, though weak, in the sun, and by the
lines, which appear[346] at
, and increase in intensity for all cooler stars. The
line is at 4555, and its behavior is difficult to trace, as it is much blended.
THE RARE EARTHS (57-71)
The spectra of the rare earths are so rich in lines that spurious identifications with lines in stellar spectra are often likely to occur. Numerous attributions to lanthanum (57), cerium (58), and neodymium (60) are given in Rowland’s table. The occurrence of some of these elements has also been definitely established in the spectra of certain stars. Kiess[347] has demonstrated the presence of europium (63) and of terbium (65) in
