Notable neutron stars
Neutron stars are formed by the gravitational core collapse of massive stars during a Type II supernova. As such, they are dead (degenerate) because they no longer generate fusion. Different types include:
Pulsar - Rapidly spinning neutron star
Double pulsar - Two rapidly spinning neutron stars orbiting each other
Millisecond pulsar - Pulsar that rotates more than a thousand times a second
X-ray binary pulsar - X-ray spectrum pulsar with a stellar companion
Magnetar - Highly magnetized neutron star
Merger - Two neutron stars colliding creating massive gravitational waves
HR 6819 is actually a black hole and two stars forming a trinary system. These stars are visible to the naked eye.