What is a Neutron Star: Understanding its Formation, Types and Characteristics

Neutron stars are the smallest and densest star with a diameter of about 20 kilometers. It is the collapsed core of a giant star that goes under a supernova explosion and releases enormous heat before collapsing. It is packed with more mass than the sun and a single scoop of it can weigh around a billion tonnes on earth. There are many fascinating facts about neutron stars that make them interesting for kids. In this article, we will explore how neutron stars are formed, their types and unique properties that make them different from other stars.

Table of Contents

• What is a Neutron Star
• How are Neutron Stars Formed
• Properties of Neutron Stars
• Types of Neutron Stars

What is a Neutron Star

A neutron star is a dense star completely made up of neutrons. The radius of a neutron star ranges between 11 to 12 kilometers but their mass is approx 2 times the mass of the sun. It is a small star that spins very fast and can emit beams of electromagnetic radiations. Such a type of neutron star is called a pulsar neutron star. There are other types of neutron stars, such as magnetars and X-ray binaries, that we will learn about in the next section.

How are Neutron Stars Formed 

Neutron stars are formed from the most violent events in the cosmos: a core-collapse supernova. When a massive star with a size 8 to 20 times more that the sun exhausts its nuclear fuel, it collapses under gravity releasing enormous amounts of heat and turns into a small star called a neutron star. This new star formed has a diameter less than 20 kilometers and a very high mass.

Properties of Neutron Stars

• Mass: The neutron stars are extremely dense collapsed giant stars with a mass ranging between 1.4 to 2.3 times the solar mass. 

• Size: These stars are around 12 miles or 20 kilometers in diameter, which is roughly the size of a small city or an island.

• Gravity: The gravitation force of a neutron star is 20 billion times earth’s gravitational pull. It is very high: approx 2×10¹¹ times stronger than that of earth’s.

• Density: These are extremely dense stars and are the densest object scientists can observe directly in the universe.

• Surface Temperature: The surface temperature of a newly transformed neutron star can be around 10 million K or more.

• Magnetic Field: With extremely high magnetic field of 10⁸ to 10¹⁵ gauss, neutron stars are among the most powerful magnetic environments in the cosmos.

Types of Neutron Stars

Based on their behaviour neutron stars can be classified into different types:

• Pulsar: The neutron stars that emit electromagnetic radiation such as radio waves are called pulsar. As the pulsar star spins it releases energy in beams that appear in space like a lighthouse.
  
  
• X-ray Binaries: These neutron stars are quiet cooling objects that do not emit detectable pulses. They simply drift through space with a faint thermal X-ray glow.

• Magnetars: These are pulsar neutron stars with extremely high magnetic fields. The radiation they emit is the energy coming from these powerful magnetic fields.
  
  
• Millisecond Pulsars: A high speed neutron star that completes one rotation in 1 to 10 milliseconds is called a millisecond pulsar. It can spin about 700 times per second and 6000 to 60,000 times in one minute.

While the neutron star retains a physical surface and a finite size, its matter remains observable and measurable. Black hole is an astronomical object formed as remnants of a collapsed star that is invisible and has a very high gravitation pull.