Question

Consider the following statements regarding neutron stars :-

1. If the core of the collapsing star is less than the Chandrasekhar’s limit, it leaves behind a neutron star.

2. In a neutron star, the core collapses, crushing together every proton and electron into a neutron.

3. Both pulsars and magnetars are the types of neutron stars.

4. The magnetic field of a pulsar is 1000 times stronger than that of a magnetar.

Which of the above statements is/are correct Select the correct option using the options given below:
(a) 1, 2, 3 and 4
(b) 2, 3 and 4 only
(c) 1 and 4 only
(d) 2 and 3 only​

Answer 1

Option D - 2 and 3 Only

• Statement 1 is incorrect :- If the core of the collapsing star is between about 1.4 and 3 solar masses, these newly-created neutrons can stop the collapse, leaving behind a neutron star.

• Statement 4 is incorrect :- The magnetic field of a magnetars is 1000 times stronger than that of a pulsar and trillions of times of the Earth’s magnetic field.

■ Explanation :-

• Both black holes and neutron stars are corpses of stars that died in catastrophic explosions known as supernovas, outbursts that can make a star briefly outshine all of the other stars in its galaxy. When a star goes supernova, the core of its remains collapses under the strength of its own gravitational pull. If this remnant is massive enough, it may form a black hole, which has gravity so powerful that not even light can escape it. A less massive core will form a neutron star, so named because its gravity is strong enough to crush protons together with electrons to form neutrons.

• When stars more than 1.4 times (Chandrasekhar’s limit) to 3 times as massive as the sun explode in a violent supernova, their outer layers can blow off in an often-spectacular display, leaving behind a small, dense core that continues to collapse. Gravity presses the material in on itself so tightly that protons and electrons combine to make neutrons, yielding the name “neutron star.” Stars with higher masses will continue to collapse into stellar-mass black holes.

• Most neutron stars are observed as pulsars. Pulsars are rotating neutron stars observed to have pulses of radiation at very regular intervals that typically range from milliseconds to seconds. Pulsars have very strong magnetic fields which funnel jets of particles out along the two magnetic poles. These accelerated particles produce very powerful beams of light. Often, the magnetic field is not aligned with the spin axis, so those beams of particles and light are swept around as the star rotates. When the beam crosses our line-of-sight, we see a pulse – in other words, we see pulsars turn on and off as the beam sweeps over Earth.

• Another type of neutron star is called a magnetar. In a typical neutron star, the magnetic field is trillions of times that of the Earth’s magnetic field; however, in a magnetar, the magnetic field is another 1000 times stronger.

• Within about 1,000 kilometres of a magnetar, the magnetic field is so strong it messes with the electrons in human atoms. one would literally be torn apart at an atomic level. Even the atoms themselves are deformed into rod-like shapes.

Hope It helps you.