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crust of neutron stars
I read a recent article in Science News about how a certain neutron star was shown to have a crust whose thickness is about 1/3 the radius of the star. From this, the researchers concluded that the core really consists of neutrons, not of other particles. This was based on certain models. Question 1: Where are these models described? The article also said that the crust was made of iron. Question 2: What state is this iron in? Question 3: Is it pure iron? Apart from the intrinsic interest in the star, as reported in the article, I'm somewhat influenced by the recent reports on the ice continents, methane seas and Earthlike weather (albeit colder) of Titan and I'm wondering whether there could be much hotter places that could be described as having seas, continents, weather and erosion. So, let's take this neutron star for a moment. Question 4: Are there variations in the thickness of the crust? Question 5: Do neutrons bubble up through the crust? Since it was hard enough for them to figure out that it has an iron crust in the first place and to measure its thickness, I don't expect that anyone necessarily knows the answers to these questions. But it is interesting to speculate about it. At any rate, I'll be glad to know about what is known about things like that. Question 6: What is the density of the iron in the crust of the neutron star? I'm not sure but I think I've heard about carbon stars and maybe oxygen stars. I read in another issue of Science News that under sufficient pressure, something like 100 Gigapascals, oxygen becomes a red superconducting metal. Question 7: If there are oxygen stars, would one expect any of the oxygen to be in that state? -- Ignorantly, Allan Adler * Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and * comments do not reflect in any way on MIT. Also, I am nowhere near Boston. |
#2
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crust of neutron stars
Allan Adler a écrit :
[snip] Apart from the intrinsic interest in the star, as reported in the article, I'm somewhat influenced by the recent reports on the ice continents, methane seas and Earthlike weather (albeit colder) of Titan and I'm wondering whether there could be much hotter places that could be described as having seas, continents, weather and erosion. [snip] Look at this article in space.com http://www.space.com/scienceastronom...ry_monday.html There you find iron vapour condensing into iron rain in dwarf stars... Really a NICE Weather... You go out to take a walk and it rains molten iron. Inconvenient, even your titanium umbrella starts melting. :-) |
#3
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crust of neutron stars
Thanks for the pointer to the article on the iron weather on brown dwarfs.
I gather there is nothing we would consider ground for the iron to rain on. If a substance is in crystalline form, we have a right to consider it solid, and maybe we also consider something like glass a solid, an amorphous one. On the other hand, to talk about stuff like continents and weather and erosion, these notions might not be appropriate. Here are two illustrations of what I mean by this: (1) If someone jumps into the water from a very great height, they will experience hitting the water in much the same way as if they hit concrete. (2) The continents, which to our perception are so solid and immutable, move very slowly over the lower SiMa layer (to use Wegener's terminology for the substrate that the continents slide on). That SiMa layer is also rock, but has a viscosity and flows under the weight of the continents. So, for this context, it seems that we also have to take into account the time scale when talking about how solid or liquid (or gaseous) things are. In the case of Titan, the rate at which weather, as we know it, takes place is very slow. In the case of the brown dwarf, it seems that the time scale is very fast. So, what I'm wondering is whether one can speak of relatively slower moving components being eroded by relatively faster moving components, for example, in the context of the crust of a neutron star or the surface of a brown dwarf. -- Ignorantly, Allan Adler * Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and * comments do not reflect in any way on MIT. Also, I am nowhere near Boston. |
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