2 Observational material and line identifications

Four nitrogen-baked IIa-O 4.3 ${\mbox \AA}$ mm^-1 spectrograms (Ce 22760, Ce 22922, Ce 23322 and Ce 23760) of HD 133029 and four (Ce 21996, Ce 22005, Ce 22015 and Ce 22557) of HD 192913, obtained by SJA with the coudé spectrograph of the 2.5 m telescope of Mount Wilson Observatory were used in this study. The region covered is approximately $\lambda\lambda3760-4650$.

There are no published line identifications of HD 133029. The stellar lines were identified with the aid of standard sources, especially, A Multiplet Table of Astrophysical Interest (Moore 1945). Lines of H I, He I, C II, Mg I, Mg II, Al I, Si II, S II, Ca II, Ti II, Cr I, Cr II, Mn II, Fe I, Fe II, Fe III, Ni II, Y II, Sr II, Zr II, Ce II, Nd II, and Eu II are definitely present. Those of Si III and Hg II are probable identifications.

Jaschek & López-García's (1966) detailed identification study of HD 192913 for $\lambda\lambda~3754-4670$ based on a 4.5 Å mm^-1 Palomar Observatory spectrogram listed lines of H I, C II, Mg II, Al I, Si II, Ca II, Sc II, Ti II, V II, Cr I, Cr II, Mn II, Fe I, Fe II, Fe III, Sr II, Y II, Zr II, Eu II, Gd II, Hg I, and Hg II. Cowley & Crosswite (1978) (see also Ryabchikova et al. 1990) identified lines of several intermediate and heavy singly and doubly ionized rare-earth species, in particular Ce III, Nd III, Sm III, Gd III, Dy III, Ho III, Er III, Tm III, and Yb III.

Equivalent widths and H$\gamma$ profiles were read directly from the intensity tracings which were made with the PDS microdensitometer of Kitt Peak National Observatory. Those from different spectrograms of the same star were averaged to increase the signal-to-noise ratio, but this means averaging over any spectral variability. As the H$\gamma$ profiles were assumed to be symmetric about the line core, their wings were averaged.