Pulsar

A pulsar is a rotating neutron star which emits detectable electromagnetic radiation, including radio waves. The radiation intensity varies with a regular period, corresponding to the star's rotation period.

A rogue pulsar passed through the Mestiko system in 2365, doing significant damage to the planet Mestiko, despite the best efforts of the Federation and the crew of the USS Enterprise. (TOS eBook: Mere Anarchy: Things Fall Apart)

A pulsar nearby the Andorian's Thraz Outpost was the source of the Thraz Streamer, a flume of faster-than-light tachyons. (TOS short story: "Ambition")