There isn't a specific, singular name for a scientist who studies astrophysics. They are generally called astrophysicists.

Here's why:

* Astrophysics is a specialized field within astronomy.

* Astronomers study all aspects of celestial objects and phenomena.

* Astrophysicists focus on the physical properties and processes of celestial objects, applying physics to understand them.

So, while "astronomer" is a broader term, "astrophysicist" is the specific title for someone who researches the physics of the universe.