Answer the following question given this paragraph: 

We have been able to take pictures of only a few exoplanets. Most are discovered because of some tell-tale signs. One sign is a very slight motion of a star that must be caused by the pull of a planet. Another sign is the partial dimming of a star’s light as the planet passes in front of it.


Q: What celestial body is often discovered because it causes a star to move or to dim?


A:
exoplanet