ON THE AFFINITIES OF THE DIFFUSE INTERSTELLAR BAND AT 5778-A

If the broad diffuse interstellar bands at 4430 and 5778 A belong to the same family, the ratio of the equivalent widths will be constant from star to star and it should not be possible to find a variable with which the ratio is correlated, but such a variable is found here in an analysis of existing measurements. The ratio is strongly correlated with the ratio of lambda4430 to lambda5797, so lambda5778 appears not to be in the same family as lambda4430. Similar comparisons suggest that lambda5778 is not in the same family as lambda5780 either, but might belong with lambda5797. All the other bands in the same family as lambda5797 are narrow, so two possibilities are apparent: either the carrier of lambda5778 has narrow transitions as well as broad, or it is not the carrier of lambda5797 even though it has a similar interstellar habitat. According to the fullerane theory, different bands are carried by different hydrides of the fullerenes such as C60Hm, and it follows that the carrier of lambda5778 bears fewer hydrogen atoms than that of lambda4430.