astarīs from √stṛ. Often the second, or second and third, class is represented by only an isolated form or two.
828. This is, of the three principal divisions of aorist, the one least removed from the analogy of forms already explained; it is like an imperfect, of the root-class or of the á-class, without a corresponding present indicative, but with (more or less fragmentarily) all the other parts which go to make up a complete present-system.
829. a. This formation is in the later language limited to a few roots in आ ā and the root भू bhū, and is allowed to be made in the active only, the middle using instead the s-aorist (4), or the iṣ-aorist (5).
b. The roots in आ ā take उस् us as 3d pl. ending, and, as usual, lose their आ ā before it; भू bhū (as in the perfect: 793 a) retains its vowel unchanged throughout, inserting व् v after it before the endings अम् am and अन् an of 1st sing. and 3d pl. Thus:
For the classical Sanskrit, this is the whole story.
830. In the Veda, these same roots are decidedly the most frequent and conspicuous representatives of the formation: especially the roots gā, dā, dhā, pā drink, sthā, bhū; while sporadic forms are made from jñā, prā, sā, hā. As to their middle forms, see below, 834 a.
a. Instead of abhūvam, RV. has twice abhuvam. BhP. has agan, 3d pl., instead of agus.
831. But aorists of the same class are also made from a number of roots in ṛ, and a few in i- and u-vowels (short or long) —