Neutron Stars & Pulsars

Question 1

Describe Pulsars.

Answer 1

regularly pulsating radio sources. rapidly rotating, highly magnetised.

Question 2

What kind of periods are observed from Pulsars and what do they imply?

Answer 2

a few tenths of seconds to a few seconds. implies a compact object. spin down slowly with increasing period.

Question 3

How can we obtain an equation for the period/rate of change of period?

Answer 3

Model pulsar as simple rigid magnetised sphere rotating in vacuum. Use model for energy loss rate and then equate to expression for rotational energy - > differentiated.

Question 4

What is responsible for the observed pulses from pulsars?

Answer 4

Luminosity of this emission comes from slowing down of Pulsar spin. Believed to be by curvature radiation. field lines and plasma rotate with pulsar but beyond some radius >c. the field lines crossing this can’t close so plasma streams away along open lines at poles.