銀河 ぎんが系内 けいない星雲 せいうんであれば
gingakei nai seiundeareba

Noun
Da Copula

The "-eba" conditional form ("if/when…") of 銀河系内星雲

1. If it is a nebula within the Milky Way; If it were a nebula within the Milky Way

Ba Conditional
Astronomy