Author Question: What evidence do we have that pulsars are neutron stars? What will be an ideal ... (Read 58 times)

robinn137 · **on:** Jul 27, 2018

What evidence do we have that pulsars are neutron stars?

What will be an ideal response?

Question 2

Acrux has an MV = 4.2 and an mV = 0.81 . Therefore, Acrux is actually brighter than we perceive it to be.

a. True
b. False
Indicate whether the statement is true or false

juiceman1987 · **Reply #1 on:** Jul 27, 2018

Answer to Question 1

Pulsars could not be ordinary stars. A normal star, even a small white dwarf, is much too big to pulse that fast. Nor could a star with a hot spot on its surface spin fast enough to produce the pulses. Even a small white dwarf would fly apart if it spun 30 times a second. The pulses last only about 0.001 second, placing an upper limit on the size of the object producing the pulse. If a white dwarf blinked on and then off in that interval, you would not see a 0.001-second pulse. That's because the point on the white dwarf closest to Earth would be about 6000 km closer to you, and light from that spot would arrive 0.02 s before the light from the bulk of the white dwarf. As a result its short blink would be smeared out into a longer pulse. Only a neutron star is small enough to be a pulsar.

Answer to Question 2

True