What does Ae mean when used in a chemical formula? In this video on slide 38 for example, the 35 minute mark, the formula appears

HAeBe


With the explaination "some chemestry has taken place..." and an infrared spectra.

What is Ae? I tried looking it up thinking it might be a common shorthand, but the only hits are answers that say "no, did you mean Al, Ag, etc.".
HAeBe stands for Herbig Ae/Be star, which is a young star before the main sequence of its formation.

The spectra of HAeBe stars show hydrogen and calcium emission lines, which are shown in the video. 

The cloud could be referring to the gas-dust envelope that surrounds the star, but I'm not an expert in this field and so I'm unsure.