Chemical composition of relativistic neutron star jets?

[Bernie G]

Is there any good information about the chemical composition of relativistic jets from neutron stars? If the chemical composition of the jets was different from the accretion material it could shed light on the process that forms the jets.

 

[davenn]

whilst not exactly what you are after, it may give you some enlightenment on the subject

http://arxiv.org/pdf/astro-ph/0305435v1.pdfDave

 

[Bernie G]

whilst not exactly what you are after, it may give you some enlightenment on the subject
http://arxiv.org/pdf/astro-ph/0305435v1.pdf Dave

Interesting link which illustrates the reason for my post. A neutron star or stellar black hole is only the size of an asteroid and hence can’t be resolved at hundreds of light years. The only features that can be seen/resolved are the jets and accretion, and glows from the surface. Analysis of the glows is very difficult. The mystery of neutron star relativistic jets is probably easier to understand than stellar back hole jets so neutron star observations could provide the answers for both.

Spectral analysis should reveal the chemical composition of the jets and the accretion. If they are different where does the change occur? Also the synchronization of the jets and accretion is easily observed, and if they are not synchronized it means a lot. The type of info I seek is like that in the following 2 links ….. where could the iron come from? Iron is what could be expected on the surface of a neutron star:

http://www.esa.int/Our_Activities/Space_Science/Black_hole_boasts_heavyweight_jets
http://www.astronomy.com/news/2015/08/neutron-stars-strike-back-at-black-holes-in-jet-contest

 

[Bernie G]

If the chemical composition of ultra relativistic jets was electrons and positrons, would it be possible for the disintegration of neutrons to produce this directly?

 

[Bernie G]

This is what I posted on another question, and think its relevant here:
IMHO if a jet has a velocity >0.9c it should be composed mostly of tiny particles like electrons, positrons, neutrinos, quarks, other leptons, etc. If full size atoms are present in a >0.9c jet they are probably small in quantity and just going along for the ride.

 

[mfb]

If the chemical composition of ultra relativistic jets was electrons and positrons, would it be possible for the disintegration of neutrons to produce this directly?

This would violate baryon number conservation.

IMHO if a jet has a velocity >0.9c it should be composed mostly of tiny particles like electrons, positrons, neutrinos, quarks, other leptons, etc. If full size atoms are present in a >0.9c jet they are probably small in quantity and just going along for the ride.

At the energies needed to accelerate particles to 0.9 c, atoms will rarely keep all their electrons, they are just stripped too easily. You still get protons and other nuclei.

 

[Bernie G]

At the energies needed to accelerate particles to 0.9 c, atoms will rarely keep all their electrons, they are just stripped too easily. You still get protons and other nuclei.

Yes, but do >0.9c jets have a representative number of protons or other nuclei? If so almost all the mass in the jet would be nuclei. It would be amazing to have a significant number of protons moving at 0.999c although it might not be so amazing to have occasional protons carried along in a 0.999 jet of lepton like particles.

 

[mfb]

Cosmic rays are mainly protons and a few other nuclei - with energies up to 10²⁰ eV, or 0.9999999999999999999999999999999 c (iron at 10²⁰ eV, digits counted). What is 0.999c compared to that?

Here are nuclei in jets

 

[Bernie G]

Amazing stuff, supernovae explosions squirting lots of nuclei. That link on jet composition isn't clear if there are a trace amounts or a lot of nuclei in that jet or if its mostly leptons. It would be good to know if >0.9c jets from neutron stars are mostly leptons and/or if they have a lot nuclei. That might shed some light on how can a neutron star produce >0.9c jets and where do the leptons come from?

 

[mfb]

Well, my link goes to the description for the public, the actual publication will have more details (and also references to previous work done).

 

[Bernie G]

I'm not knocking it, its a good link, thanks. Note the jet speed in that link is 0.66c. It would be amazing if most of the mass in a >0.9c jet were nuclei.

 

[patellar-myotatic]

This would violate baryon number conservation.
At the energies needed to accelerate particles to 0.9 c, atoms will rarely keep all their electrons, they are just stripped too easily. You still get protons and other nuclei.

If the jets near the accretion disc maintain a positive charge, eventually free electrons are going to be accelerated from the galaxy toward the charged jets. At perhaps some great distance they will recombine with it.

But I don't see how the base of the jets could initially have an overall neutral charge. The accretion disc must be embedded in a powerfully confining magnetic field that turns particles according to charge and mass.