4 ms·
"For instance, the mountains on the surface of the Crab pulsar could be as high as a few meters, while in PSR 1957+20 they cannot exceed a few microns!" What's
by rwallace 12y ago
"For instance, the mountains on the surface of the Crab pulsar could be as high as a few meters, while in PSR 1957+20 they cannot exceed a few microns!"
What's the reason for the difference? What causes one pulsar to be able to have mountains a million times as high as another?
- fragsworth 12y agoIt's mostly due to the total mass of the star, since a more massive star has greater gravitational force at its surface, overwhelming the structural forces in the particles.
- rwallace 12y agoThat doesn't sound right. Neutron stars vary by no more than a factor of two in mass; that's not enough to account for six orders of magnitude variation in height of highest mountains.
- agrona 12y agoFrom my reading of it: >The size of the highest mountain of order ∼ εR can be roughly estimated from the inequality (292). >P, P˙ and I are, respectively, the pulsar’s period, period derivative and moment of inertia [in inequality (292)]. Those terms are all just multiplied together in the inequality, so changes in any of them could affect epsilon (the "dimensionless parameter characterizing deformations of the star")