Definition

Noun: A pulsar is a type of celestial object, specifically a highly magnetized, rotating neutron star. It is the collapsed core of a massive star that has exploded as a supernova. Pulsars are extremely dense, relatively small, and emit beams of electromagnetic radiation from their magnetic poles. As they rotate, these beams sweep through space like a lighthouse; if one of these beams points toward Earth, we observe it as a regular, repeating pulse of radiation.

Examples of Usage

• The first pulsar was discovered in 1967 by Jocelyn Bell Burnell.
• Astronomers use the incredibly regular pulses from a pulsar to study the physics of extreme states of matter.
• The pulsar at the heart of the Crab Nebula rotates about 30 times per second.

Advanced Usage

• Millisecond pulsar: A type of pulsar with a very short rotation period, typically spinning hundreds of times per second. These are often found in binary star systems.
  • The millisecond pulsar's rapid spin is thought to be caused by accretion of matter from a companion star.
• Pulsar timing array: A set of widely separated pulsars monitored to detect low-frequency gravitational waves by looking for correlated disturbances in their pulse arrival times.
  • Scientists hope that pulsar timing arrays will provide direct evidence for gravitational waves from supermassive black hole binaries.

Variants and Related Words

• Neutron star (n): The broader category of stellar remnant to which all pulsars belong. A pulsar is a neutron star that emits detectable beams of radiation toward Earth.
• Magnetar (n): A type of neutron star with an extremely powerful magnetic field, often considered a subclass or a related, highly magnetic variant of neutron stars, though not all magnetars are observed as pulsars.

Synonyms

• Neutron star (though this is a broader term; not all neutron stars are observed as pulsars)
• Lighthouse star (a descriptive, non-technical term referencing its emission mechanism)

Related Phrases

• Pulse period: The time interval between successive pulses from a pulsar.
  • By measuring the pulse period, astronomers can calculate the pulsar's rotation speed.
• Pulsar wind nebula: A nebula powered by the wind of particles emanating from a pulsar.
  • The famous Crab Nebula is a pulsar wind nebula, energized by the pulsar at its center.

Noun

1. a degenerate neutron star; small and extremely dense; rotates very fast and emits regular pulses of polarized radiation