Sunday, May 05, 2019

[gwulsqjy] Pulsars

Pulsars presumably beam from their north and south magnetic poles.  But in order for them to appear to pulse to an observer, their axis of rotation must not be aligned with their magnetic axis.  What determines the magnetic poles of a neutron star?

One could have imagined the centrifugal forces of rotation somehow causing the axes to move into alignment, but clearly that is not happening.  One can also imagine the centrifugal forces causing magnetic poles to move to the equator, though we would still need a mechanism to choose which points on the equator.  Maybe random.

If the neutron star is part of a binary system, its rotation axis could change as matter accretes from the companion: the angular momentum of the system gets transferred onto the neutron star.  How quickly after seeing a supernova have we seen its pulsar?  And certainly we have seen pulsars that are not part of a multiple star system.

Maybe the rotational axis of a neutron star is determined by some anisotropy of its supernova.

Is the fact that the beams of a neutron star are not at its rotational poles similar to how sunspots on the sun tend to form at middle latitudes (butterfly diagram)?

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