Progressive clue challenge

How quickly can you identify the hidden word?

Begin with a broad grammatical clue. Reveal more only when needed. Fewer clues and fewer wrong guesses produce a higher score.

100
It is used as a noun.
It begins with “A” and contains 8 letters.
Definition: A fixed star of the first magnitude in the constellation Bootes.
It ends with “S”.
Clue 1 of 4 is visible.
Another word