Object Weight on Magnetar vs Neutron Star: Attract or Repel?

[kuartus4]

TL;DR

A non magnetar, normal neutron star

Probably a misguided question, but would the intense magnetic field of a magnetar increase the overall pull an object would feel at the surface of the magnetar as compared to a regular neutron star? Or would it possibly lessen the amount of gravitational pull the object would feel at the surface, due to it being repelled by the magnetic field?

So I guess this boils down to, does the magnetic field repel or attract the object, and how much in comparison to the stars gravity?

 

[DaveC426913]

Is the object ferrous?

 

[kuartus4]

Is the object ferrous?

Lets say yes.

 

[PeterDonis]

does the magnetic field repel or attract the object, and how much in comparison to the stars gravity?

There are actually two effects here. First is the ordinary EM field effect, which will depend on the nature of the material and its charge, if any.

Second is the fact that the magnetic field itself carries energy, which means it is itself a source of gravity--i.e., it will increase the total stress-energy of the neutron star as compared to a neutron star otherwise identical but with no magnetic field. This will increase the effective "mass" of the neutron star in terms of determining its gravitational pull.

 

[kuartus4]

There are actually two effects here. First is the ordinary EM field effect, which will depend on the nature of the material and its charge, if any.

Second is the fact that the magnetic field itself carries energy, which means it is itself a source of gravity--i.e., it will increase the total stress-energy of the neutron star as compared to a neutron star otherwise identical but with no magnetic field. This will increase the effective "mass" of the neutron star in terms of determining its gravitational pull.

If I'm interpreting you correctly, a magnetar has higher surface gravity than a non magnetar, all else being equal?

I remember experiments where normally non magnetic objects(like small animals) can be levitated using very powerful magnetic fields. Would a magnetar's magnetic field have a similar anti gravity effect on non magnetic objects near the star(assuming they won't be obliterated by the extreme conditions)?

 

[PeterDonis]

If I'm interpreting you correctly, a magnetar has higher surface gravity than a non magnetar, all else being equal?

If you're only considering the gravitational effects of stress-energy, yes.

I remember experiments where normally non magnetic objects(like small animals) can be levitated using very powerful magnetic fields.

This effect has nothing to do with gravity, and is certainly not "antigravity". It's just inducing magnetic fields inside the normally non-magnetic objects that then cause normal magnetic repulsion between the objects and the source of the magnetic field.

 

[kuartus4]

If you're only considering the gravitational effects of stress-energy, yes.This effect has nothing to do with gravity, and is certainly not "antigravity". It's just inducing magnetic fields inside the normally non-magnetic objects that then cause normal magnetic repulsion between the objects and the source of the magnetic field.

Right, thank you. I just meant in the sense that it works against the pull of gravity. Am I on the right track assuming the magnetar would induce a magnetic repulsion on something like a chunk of carbon which would at least partially counteract the amount of gravity it feels? By analogy, in the way buoyancy counteracts the amount of gravity a person feels in water.

 

[PeterDonis]

Am I on the right track assuming the magnetar would induce a magnetic repulsion on something like a chunk of carbon which would at least partially counteract the amount of gravity it feels?

I believe the magnetic field of a magnetar would act on a piece of non-magnetic matter similarly to the magnetic fields in the "levitation" experiments you mention, yes. But I have not looked at the properties of magnetars in any detail.

 

[DaveC426913]

This might be a good time to look at Earth-bound demos.
Google ActionLabs Ferrofluids Osmium


Action Lab guy demonstrates how Osmium - the heaviest metal on the periodic table - can be made to float in a ferro-fluid, which - when minding its own business - is little more dense than water.