The type of star that acts like a lighthouse, periodically emitting radio waves into space, is called a pulsar.

Here's why:

* Rotating Neutron Stars: Pulsars are incredibly dense, rapidly rotating neutron stars. They are the collapsed cores of massive stars that have exploded as supernovas.

* Magnetic Fields: Pulsars have extremely strong magnetic fields. As they rotate, these magnetic fields sweep across space, like a lighthouse beam.

* Radio Emission: The rotating magnetic fields accelerate charged particles, causing them to emit radio waves. These waves are focused into beams along the magnetic poles.

* Periodic Pulses: Since the pulsar is rotating, these radio beams sweep across space, hitting Earth periodically. This creates the impression of a "pulsed" signal, hence the name "pulsar".

So, pulsars are like cosmic lighthouses, but instead of light, they emit radio waves in a regular, pulsing pattern.