What specific signal are astronomers looking for during a transit event?

Answer

A tiny dip in brightness

A transit event occurs when a planet passes in front of its host star from the observer's perspective. This causes the star's brightness to dim slightly for a short period. Detecting this minute change is the hallmark of the transit method, which requires extreme precision to distinguish from natural stellar variability.

What specific signal are astronomers looking for during a transit event?
Andromedagalaxyplanet