When neutron stars fuse, there's gold

[PB666]

http://www.skyandtelescope.com/astronomy-resources/astronomy-questions-answers/science-faq-answers/galactic-gold-mine-explains-the-origin-of-natures-heaviest-elements/

 

[Thomassino]

Interesting. But heavy elements are relatively abundant. Neutron star collisions probably aren't enough to suffice for that, and they're extremely rare. 

[Shpaget]

I thought that we had that question answered already - supernovae.

Yes, fusion of elements heavier than iron takes more energy than it releases, but there's plenty of energy in a supernova.

[PB666]

Apparently thats not good enough for some concentartions of these heavies. BTW is not one or the other,mthere could be multiple mechanisms. 

[YNM]

With s-process and r-process taking place anytime a proton bombards a heavier nuclei, I think even before collapse some (like, a few nuclei) should've started to form.

Is there any reason why they believe some neutron star have collided in that particular galaxy ? I mean, wouldn't that means the galactic center and globular clusters more rich in those elements ?

Edited May 29, 2016 by YNM

[PB666]

I presented a link 2 or 3 months ago about binary systems, when a neutron star forms of one partner, it increases the likelihood that the other star will form a neutron star, consequently relativistic effects, something like tidal forces in the top layers of the neutron stars cause them to spiral into each other. Im not to rich on the details cause I thought the effects to be rather trivial. 

[legoclone09]

Yeah, I saw somehing about this in a TV show a few weeks ago. It's cool!

[kerbiloid]

How many neutron star collisions take place per thousand of supernovae - at least because:

• Any neutron star requires a supernova to born.
• Not every supernova results into a neutron star.
• We can watch much more potential supernova giants than neutron stars.

Looks like a next "mega-boom" theory, as most of impact theories.
Who interests in those dull supernovae, when neutron stars collision charms an imagination.

For me, its a hype perfomance.

Edited May 29, 2016 by kerbiloid

[YNM]

Gotta agree with kerbiloid here.

Anyway, original preprint from arXiv : http://arxiv.org/pdf/1512.01558v3

[Shpaget]

I'll just have to do some ballpark math to satisfy my curiosity. Correct me if you notice anything wrong with my calculation.

If we take a "standard" neutron star with the mass of 2 solar masses (10^30 kg) and slam it at Sun's escape velocity (620 km/s) into another stationary neutron star we have the kinetic energy of 1/2 (mv^2) = 3,844 * 10^41.

Compared to a hypernova energy release of 1* 10^46, it looks like we lack some energy. Fusion of heavy elements take some energy as well, so the collision would be even less energetic.

Edited May 29, 2016 by Shpaget

[PB666]

26 minutes ago, Shpaget said:

I'll just have to do some ballpark math to satisfy my curiosity. Correct me if you notice anything wrong with my calculation.

If we take a "standard" neutron star with the mass of 2 solar masses (10^30 kg) and slam it at Sun's escape velocity (620 km/s) into another stationary neutron star we have the kinetic energy of 1/2 (mv^2) = 1,922 * 10^41.

Compared to a hypernova energy release of 1* 10^46, it looks like we lack some energy. Fusion of heavy elements take some energy as well, so the collision would be even less energetic.

They are not talking about denovon synthesis or converting all of the neutron star to heavy metals, they are simply stating that there are hot spots, for example at the fusion interface were such elements can be made. Since the neutrons in a neutron star have momentum, but also the resonate into bosonic matter, which means thier wave functions superimpose, what happens when you get two massive superimpossed particles that collide at high velocity. Its exotic particle land. Its like sacrificing 99.9 % of energy to reduce order to use a small percent to create order. 

[qeveren]

11 hours ago, Shpaget said:

If we take a "standard" neutron star with the mass of 2 solar masses (10^30 kg) and slam it at Sun's escape velocity (620 km/s) into another stationary neutron star we have the kinetic energy of 1/2 (mv^2) = 3,844 * 10^41.

A typical neutron star's escape velocity, however, is around 1/3 c, which ballparks things right back up to around 2e46 J.

[kerbiloid]

1 hour ago, qeveren said:

A typical neutron star's escape velocity, however, is around 1/3 c

So, I'm trying to imagine an interstellar gas cloud able to catch golden atoms with 1/3c heat speed...

Edited May 30, 2016 by kerbiloid

[fredinno]

On 2016-05-29 at 7:59 PM, PB666 said:

I presented a link 2 or 3 months ago about binary systems, when a neutron star forms of one partner, it increases the likelihood that the other star will form a neutron star, consequently relativistic effects, something like tidal forces in the top layers of the neutron stars cause them to spiral into each other. Im not to rich on the details cause I thought the effects to be rather trivial. 

Why does a neutron star forming increase the likelihood of the other star forming a neutron star in a binary?

On 2016-05-29 at 10:47 AM, Shpaget said:

I'll just have to do some ballpark math to satisfy my curiosity. Correct me if you notice anything wrong with my calculation.

If we take a "standard" neutron star with the mass of 2 solar masses (10^30 kg) and slam it at Sun's escape velocity (620 km/s) into another stationary neutron star we have the kinetic energy of 1/2 (mv^2) = 3,844 * 10^41.

Compared to a hypernova energy release of 1* 10^46, it looks like we lack some energy. Fusion of heavy elements take some energy as well, so the collision would be even less energetic.

You don't need to fuse from hydrogen to gold, Neutron Stars are already made of neutron clusters, clumped together (with a small amount of protons), thus, all we need is for the neutron clumps to break apart from the Neutron Stars in a neutron star collision, then (hopefully) heavy elements form from the decaying neutron clumps.

13 hours ago, kerbiloid said:

So, I'm trying to imagine an interstellar gas cloud able to catch golden atoms with 1/3c heat speed...

It'd probably slow down due to drag in interstellar space...

[PB666]

2 hours ago, fredinno said:

Why does a neutron star forming increase the likelihood of the other star forming a neutron star in a binary?

The evolution of neutron star involves the radially loss with the lower mass remnant retaining most of the angular momentum, in the form of its spin. Because the neutron star is made up different phases some experience tidal forces from the adjacent star, this creates a ver strong magnetic field. According to that article, the field causes erosion of the gas in the adjacent star.

http://phys.org/news/2016-05-tides-binary-star-neutron-stars.html

I couldn't find the article i was looking for,mthe above talks about why neutron stars merge. 

http://www.nature.com/nphys/journal/v11/n12/full/nphys3574.html

http://www.nao.ac.jp/en/news/science/2014/20141014-neutronstar.html

 

 

 

Edited May 30, 2016 by PB666

[p1t1o]

To be honest, bigger news would be if neutron star collsion *didn't* create gold.

 

[pincushionman]

18 hours ago, fredinno said:

…It'd probably slow down due to drag in interstellar space...

That'd be one hell of a cloud.

[PB666]

56 minutes ago, pincushionman said:

That'd be one hell of a cloud.

If we accept that at least one of the stars in a neutron binary went SN, the we accept that there are remnants of a nebula.
Almost all 2nd and 3rd generations stars are formed as a consequence of nebula formation, so its a forgone conclusion that atoms and molecules in a nebula interact.

Therefore have gold from a star traveling out a few light years and undergoing collisions with particles in the nebula is not surprising. Gold atoms are pretty big, they have alot of electrons in their outer shell, and traveling at 0.05 to 0.3 c its not hard to strip electrons off or occasionally add electrons allowing gold to interact with surrounding material by non-collison forces creating a wake of particles that have been accelerated and slowing the gold atoms down.

A more difficult question is how do you zip up gold atoms to 0.05 to 0.3c when you have two neutron stars colliding, all but reaching the minimum limits for black hole formation.

 

[Oafman]

Would this event produce significant gravitational waves? As we become better at detecting these, can we start actively looking for such events?

[PB666]

I think the answer is, if I am reading the press stuff correctly, that they already have produced detectable.

The bigger problem right now is they need many more detectors than hey have to make these things detectable unless they are close.

 

[fredinno]

21 hours ago, PB666 said:

The evolution of neutron star involves the radially loss with the lower mass remnant retaining most of the angular momentum, in the form of its spin. Because the neutron star is made up different phases some experience tidal forces from the adjacent star, this creates a ver strong magnetic field. According to that article, the field causes erosion of the gas in the adjacent star.

http://phys.org/news/2016-05-tides-binary-star-neutron-stars.html

I couldn't find the article i was looking for,mthe above talks about why neutron stars merge. 

http://www.nature.com/nphys/journal/v11/n12/full/nphys3574.html

http://www.nao.ac.jp/en/news/science/2014/20141014-neutronstar.html

 

 

 

I still don't get it. How does the erosion of a binary star's gas make a neutron star?

1 hour ago, PB666 said:

I think the answer is, if I am reading the press stuff correctly, that they already have produced detectable.

The bigger problem right now is they need many more detectors than hey have to make these things detectable unless they are close.

 

Or just build them in space.

[PB666]

31 minutes ago, fredinno said:

I still don't get it. How does the erosion of a binary star's gas make a neutron star?

Its not simply erosion of the stars gas, its the selective accelerative evolution of the second stars hydrogen, dueterium, helium and finally carbon and the heavier elements. The adjacent star may have captured some of the gas emitted by the first star during its SN, it may have picked a fair compliment of heavier elements, the magnetic field is altering its composition, and it may not go through typical SN decay as with the primary star.

This is mentioned in the Wiki article but its not my source, I could not find the original article, at the time I thought it was trivial and speculative and didn't repost it here. It should have been from March or April of this year, I searched Reddit could not find it (though like most search engines, including this groups, really sucky). And Beeb unfortunately removes articles and replace them with new identifiers.

The best I can do right now is the wiki.