Starship Asterisk*

At the bottom of the page in the link above, be sure to click on "next lecture". It will show you what happens when the core reaches the iron stage!

BOOOOOOOOM!!!!

gary

Hello nutty star


Thank you again,,,,,,,,,,seems quite logical

http://www-astronomy.mps.ohio-state.edu ... imass.html

But! some stars go though more than one shedding of layers.

The question is does the core remain in an ultra dense state made up of neutrons or does it collapse again into an UDM.

Iron I thought is produced in the outer core layer and not in the core.

It goes to show that the more you learn the more you feel like an EMU having its head in the sand.

Smile,,,,,,,,,,,thats me the EMU

Happy Easter Harry,

Nice Weather for Easter!

Iron, I thought, is made in the core and that's when the star becomes unstable as gravity is unable to keep up.

Starnut,

I very much appreciate the link to Dr. Pogge's website !

Having a succinct listing of the stages of stellar life and death and transfiguration as he puts it ! is extremely helpful.

I had that basic concept in my head, but many of the finerpoints were missing. Like the shockwave in nova progression. This makes a most excellent quick summary to explain to someone else the 'mainstream' astrophysics interpretation of stellar internal processes.
As my own organization of events is no where near so well organized nor accurate ! Empower knowledgeability !!!

Yesterday was such a nice calm sunny day, I decided to paint the house; a project under procrastination for some time now. 8 hours later it was 70% done, a quick wire brushing was the hard part. Today I have a slight sunburn ! And appreciate the stellar inner workings of energy release in a brand new way !!!

Oh, that brings to mind in 1955 how Professor Hottle in Massachusetts was one of the main cooks at a clam bake and lobster fest at the seashore one sunny summer day! He was a professor of thermal engineering at MIT? some big name school back there; anyway he was shirtless in the cooking area all afternoon having the time of his life ! He was in his 60's or so, and he got a really severe sunburn !!! He was as red as a boiled lobster !! Of course he has the skin tone of someone who is at his desk or indoors 24/7; and was most vulnerable. What makes it so funny is "he should have known !! " , of anybody there he would be the guy to know about that !

Well, if the glucosamine does its job I'll be able to finish the house today, provided my own sunburn doesn't get in the way!

Some days I'd rather paint the house than do physics.

Kovil

Hello All

Happy Easter to one and all.

Thanks astroton, long life and happiness


With respect to the iron,,,,,,,,,,you maybe right.

But! I thought the core would be to dense to allow for any atomic structure to remain stabel. Maybe I'm wrong.

Have to find some sand.

How is gold and other elements/substances, beyong the iron, made ???

Neutron star mergers have been put forth for the best source of gold. These mergers may also the source for short duration gamma ray bursts.

Dave

Iron accumulates at the core of high-mass stars due to a few reasons. First, it's produced there as the 'ash' of silicon fusion, the last fusion stage of large stars. Second, it's the most dense element being produced within the star (by fusion), so it tends to 'sink to the bottom' as it were. And third, even once fusion ceases in the core, silicon fusion continues in a shell around it, and this rains more iron down onto the rapidly growing core.

The core will remain stable until it exceeds the Chandrasekhar limit, I believe (I'm not entirely certain of this). However, once enough iron builds up, the mass of the core exceeds this limit and it very suddenly collapses into (more or less) a neutron star. The outer layers of the star fall inward at nearly half the speed of light, crash into this surface, and rebound. This is the beginning of a supernova explosion. But what truly drives the supernova is the massive release of neutrinos from the core, as protons and electrons combine to form neutrons. This wave of particles blasts the outer layers of the star apart in a huge shockwave.

This is also where gold is generally produced, along with most of the other elements heavier than iron. This blast of neutrinos reacts with the nuclei of other atoms in the stellar material, causing nuclear reactions that build up heavier materials (nucleosynthesis). Many of these products are themselves radioactive, and will decay into other heavy elements.

Kind of strange to think that all your jewellery came from inside a dying star someplace...

I'm not entirely certain what happens in the case of a dying star where the core mass grows rapidly enough to exceed the Tolman-Oppenheimer-Volkoff limit. It should promptly collapse into a black hole, I would think. This is one of the theoretical sources of those mysterious Gamma-Ray Bursts we keep finding across the sky: a 'hypernova'.

ta152h0

I mentioned the next part of Pogge's lecture in my last post. It explains how the rest of the periodic table is created during a supernova. I will give the link here.

http://www-astronomy.mps.ohio-state.edu ... rnova.html

Dave H

I am not sure if a merger of two neutron stars can produce anything but electromagnetic radiation and gravity wave and possibly a black hole! I would think that the combined gravity would be too strong to allow any matter to escape.

gary

Qev

Not only jewelry, but also you, me, and everything else. We are all made of stardust!

gary

I got you on this one Starnut I knew I had read it some place and lo an behold it be our very own beloved APOD

http://antwrp.gsfc.nasa.gov/apod/ap010405.html

Dave

Hello All

RE link:
http://antwrp.gsfc.nasa.gov/apod/ap010405.html

Where did the gold in your jewelry originate? No one is completely sure. The relative average abundance in our Solar System appears higher than can be made in the early universe, in stars, and even in typical supernova explosions. Some astronomers now suggest that neutron-rich heavy elements such as gold might be most easily made in rare neutron-rich explosions such as the collision of neutron stars

It talks about the early universe. Makes an assumtion that the Big Bang theory is true.
The universe is ageless and recyclic in my opinion. So rather than assuming age, its better to look at the actual process out there.


I had these links in my comp:
Neutron star
http://www.space.com/scienceastronomy/n ... 31203.html

Star birth

http://archive.ncsa.uiuc.edu/Cyberia/Bima/StarForm.html
http://www.stsci.edu/stsci/meetings/shst2/ballyj.html
http://cfa-www.harvard.edu/swas/science1.html
http://antwrp.gsfc.nasa.gov/cgi-bin/apo ... +Formation
http://www.plasmaphysics.org.uk/researc ... mation.htm
http://www-astronomy.mps.ohio-state.edu ... imass.html

Star death

http://archive.ncsa.uiuc.edu/Cyberia/Bi ... Death.html
http://www-astronomy.mps.ohio-state.edu ... rnova.html

Dave,

Now I remember that APOD posting. Gads, was it 5 years ago?! Thanks for the reminder. Unfortunately, some of the links in the explanation no longer exist. There is a neat movie of a neutron star merger in the link "collision" showing the two stars merging over (!) the Atlantic Ocean, an impossible scenario! At the end of the movie, the merged neutron star disappears, turning, I guess, into a black hole.

But that still doesn't explain how the "decompression of neutron star material" during the merger could enable the neutrons to escape the very deep gravity well! After all, the escape velocity for a neutron star is 1/2c! Is there a process by which a stellar event can accelerate heavy matter like neutrons and protons to such high speed?

gary

Hello Starnut

The drive comes from the spin creating jets that eject material out.


http://skyandtelescope.com/news/article_1627_1.asp

http://universe.nasa.gov/press/2003/030220a.html


Neutron star collision
http://www.space.com/scienceastronomy/n ... 31203.html

Hello All,

This KBoooooooooooom is more interesting....

http://www.csmonitor.com/2002/1120/p01s02-ussc.html

This Professor has interesting things to say about neutron stars and GRB's. From what I gather these stars have parts core, surface etc.... when they merge to form black holes perhaps the cores merge right through the less dense surface stuff mimicking the hyper nova black hole inside the still existing star for a brief moment picture. That matter that is left out of the black hole formation clogs at the event horizon super heats and blows. Angular momentum has to factor in big also. It’s all way outside of my league but what I do know is that black hole aren’t very efficient eaters and stuff gets clogged up trying to get in, sort of like shoppers trying to get into the Wal-Mart in the day after thanksgiving sale.

http://www.astro.umd.edu/~miller/nstar.html

Dave

Hello All

Nothing gets clogged up.

In time all will be sucked in. Where could they run and hide.
Its part of the recycle.

The clogging up is what is required to cause black holes to be some of the most luminous objects in the universe. But all in all black holes have a tiny overall effect.most the mass of the 5% of knowable stuff in the universe is cold dust and gas (very disfused,dark and boring).floating in the incrediblly large space that separates the galaxies. The point is the universe is mainly empty, at least of knowable stuff.

Hello Dave

Black holes, neutron stars, stars etc are made from plasma.
Plasma makes up about 95% of the mass that we see.

Black holes we cannot not see. As matter breaks up way before it enters the black hole it realeases large amounts of light and this is what we see.

Harry,
To some extend we are saying the same thing , I think the key phrase here is acceleration disk.But in the case of our giant meighbor Eta Carinae the core of the star will colapse instantly into black hole while the star is still shining and as out lying matter starts to fall in it locks into a super heating spherical shell at the event horizion of the black hole.The heat and pressure reaches very high levels and in a instant there is a cascade of events that lead to the largest explosions in the universe.

sounds a lot like a GRB

Yes this is a GRB and allow me to correct myself wnen I say Eta Carinae "will" this is impossible to know because it might of already have done so thousands of years ago and it 's completly impossible to know when the event occured until the day the gamma pulse arrives which may be today!

might not be pointed at us, if it ocurrs.

so at this distance, we'll be fine as long as the poles arent pointed towards us?
I still think this is a wonderful excuse to build a gamma ray proof mini dyson sphere make it a comet catcher, too!

Well if these events are beamed witch hasn't been proven we would have to be better off. But we know so little about these events there has only been a few in which we have gotten visual light. But what we do know is Eta is huge and therefore very unstable and not that far away if we consider the amount of energy that could be released in less then 2 min.