Question on Aorist Augment

Hello, I am still fairly new to learning Greek and working through a textbook right now and it mentioned the thematic 2nd aorist always beginning with an epsilon augment or lengthened vowel. However, a couple pages later they list some examples of the 2nd aorist and I’m seeing this is not the case for every verb. ἀπέθανον for example, should it not begin with an eta if this were augment were universal? So are there just common irregularities like this or what am I missing? Thanks.

Check your textbook for the rules on applying the augment to verbs that have a prepositional prefix.

The first principal part of verb you are asking about ἀπέθανον, looks like this: ἀποθνῄσκω.

Note ἀπο as against ἀπέ. Here the epison is the application of the augment.

I’m not going any further, because your textbook will explain this much better than I can. I hope I’ve given enough buzzwords to enable you to find an explanation. If not, ask again, and the more able grammarians here will help you.

Ah, yep, that clears it up–thanks!