Estrellas tempranas deficientes de helio

Abstract

Attention is called upon a group of stars in which the spectral types and the photoelectric colors disagree, the colors being too blue for the spectral types. Although a certain number of these objects is well known -the peculiar stars of the so called ”λ4200" group- the authors found a number of additional stars definitely not peculiar but exhibiting a too blue color. The objects observed so far from La Plata can be divided into two groups whose common characteristics are the weak He I lines, corresponding to a later type (B8) than their colors indicate (B5), and whose differences consist in the strength of the C II lines. In one group, CII is normal for the colors, while in the other group it is normal for the strength of the He I lines. More objects of this group are being observed.