A star system in which one star blocks the light from another is called an eclipsing binary system.

Here's why:

* Binary: The system contains two stars.

* Eclipsing: One star periodically passes in front of the other, blocking its light from our perspective.

This blocking of light causes a noticeable dip in the overall brightness of the system, which can be observed from Earth. By studying the timing and depth of these dips, astronomers can learn a lot about the stars in the system, including their sizes, masses, and orbital periods.