Neutron Definition and 746 Threads

Hello everyone. I am trying to solve a problem whose statement reads as follows: Neutron stars have radii of ##\sim 10## km. If we assume that before the collapse the nucleus of the white dwarf precursor has a mass equal to that of Chandrasekhar, estimate the energy generated in the collapse...

If we have two objects A and B appear on the opposite sides of the equator of a planet like Earth with the same mass as Earth. Object A is a neutron star with the mass of the sun and object B is a iron cube with the mass of one gram. Will A or B hit the Earth at the same time or will one hit...

we have physical evidence for the composition of a proton because it decays from a neutron however all experiments such as https://en.wikipedia.org/wiki/Deep_inelastic_scattering etc, always involve a proton and possibly a neutron, in fact you can't accelerate a neutron without a proton...

Some new papers appeared about processes in the collision of the two neutron stars, measured in August 2017. Is now more clear, why 2 second delay between gamma rays and gravitational waves happens?

Homework Statement A beam of neutrons (moving along the z-direction) consists of an incoherent superposition of two beams that were initially all polarized along the x- and y-direction, respectively. Using the Pauli spin matrices: \sigma_x = \begin{pmatrix} 0 & 1 \\ 1 & 0 \\...

Homework Statement A sphere has a height to diameter ratio of 1.00. The greater the surface area to volume ratio of a shape, the greater the neutron leakage. To increase neutron leakage should H/D be positive or negative? Homework Equations H/D The Attempt at a Solution Positive? Good...

If this is true where is the core of that star, either a neutron star or a black hole should exist near by, right?

A 1 keV fast neutron (relative mass 1) in a moderator collides elastically with a helium atom He (relative mass 4) at rest. What is the maximum amount of energy the neutron can lose? My answer is 16/25 of 1ke but while deriving this answer I simply solved based on the question as if the...

There was a lot of discussion after the recent observation of the merger of two neutron stars about whether or not these events are the source of the heavier elements. See this thread, for example. This recent paper has some new analysis. Especially interesting is Figure 10, that I've...

Hi, The figure given below was taken from "Nuclear Systems" by TODREAS and KAZIMI. it shows the effect of neutron reflector on the thermal neutron flux radial distribution. Is this correct? Because it does not show the extrapolated distance. It seems to me that the reflector, somehow...

Hi, When U-235 captures a neutron, it may end up with a fission reaction or an excited U-236 isotope. This U-236 emits gamma rays as it goes to its ground state. What I want to learn is that how much is the contribution of these gamma rays' energy to overall fission energy. I checked the...

Homework Statement "The 2200 m/s flux in an ordinary water reactor is 1.5*10^13 neutrons/cm^2*s. At what rate are the thermal neutrons absorbed by the water?" Homework Equations (unsure) The Attempt at a Solution I know that absorption of a thermal neutron (a neutron in thermal equilibrium)...

Hello everyone I am trying to obtain the integral neutron flux based on the results obtained with MCNP (neutron spectrum calculation) for each energy bin (51 neutron energy bins). I have seen in many papers the calculation of the differential neutron flux multiplying the neutron flux results of...

I find a very interesting site that shows us what it would be like to travel to a black hole or a neutron star. https://apod.nasa.gov/htmltest/rjn_bht.html Have fun !

We just discovered the maximum mass of a neutron star, discovered after the recent neutron star merger event back in Aug. They say that the maximum mass of a neutron star is approximately 2.16 solar masses. So I always assumed that the lowest mass for one is 1.4 solar masses, the Chandresekhar...

From Wikipedia: Quark-degenerate matter may occur in the cores of neutron stars, depending on the equations of state of neutron-degenerate matter. It may also occur in hypothetical quark stars, formed by the collapse of objects above the Tolman–Oppenheimer–Volkoff mass limit for...

https://www.sciencedaily.com/releases/2018/01/180116093650.htm This article gives a maximum weight of 2.16 solar masses, and an infinitesimal addition would turn it into a Black hole. I can not find a paper to support this article so do you think it is correct?

Has anyone else heard of that gravity waves may be the result of another type of supernova remains, called a Grav-Star? It seems almost to physically mimic a neuron star but stopped just shy of becoming a black hole, yet it still has enough of a gravity well to prevent light from escaping. Is...

Neutron lifetime is approx. 880s, or 1.6 * 10^46 planks times. Also, in a "naive" model quarks fly back and forth at almost light speed, bouncing back and forth, and only a single bounce per 3.3*10^26 times is fatal to the existence of a neutron. Even this model is wrong, it shows to what...

I've seen many people who is studying it.. but why ? is there any contributions to physics at a foundamentalist level ? I mean, the properties of matter inside nêutron stars is the interesting part to theoretical physics and not the whole object right ?

Note: this is QM question, not about stellar science. I am not asking what are the lightest neutron stars found in the Universe. The same star (say, 1 sun mass) can exist both in a form of a white dwarf and a neutron star. Both states are stable. However, let's say I start to stripe outermost...

QUESTION: I read in book that in beta + decay proton decays to neutron But i can't understand how it is possible if proton mass is less than neutron mass.I read on net but it says 'quarks' and 'd u p' things which i don't study about currently. Also why it only happen inside nucleus?What...

Hello, I recently watched a video as an introduction to Feynman diagrams for my own self-interest. The video gave a link to practice problems, and one of them was as follows: In a neutron star gravitational collapse causes valence electrons to combine with protons. Draw a Feynman diagram...

The sources I've looked at claim the magnetic field is present because there are still some electrons in the neutron star. Here is how I understand their reasoning: a star's radius significantly decreases when it collapses into a neutron star, ultimately decreasing its moment of inertia. In...

So, I have this scenario: A neutron star with radius R = 13 km Time for 1 rotation is 3,150807 ms, so frequency f about 317,379008 Herz Mass 1,97 times the Sun's which is then 1,97*(1,9884*10^30) kg Extra given information: the magnetic axis is aligned with its rotational axis (not that likely...

Hi, Below are the neutron flux spectra of a nuclear reactor. In the first spectrum, y-axis is differential flux and in the second spectrum, y-axis is flux (created by multiplying differential flux by energy in MeV). As far as I have seen so far, differential flux is used commonly. I am just...

Homework Statement A neutron is passing through a thin sheet of 115In of thickness 0.01 cm. Given that the density of the sheet is 7.31 g cm-3 and that the absorption cross section is 100 barns, what is the chance of the neutron being absorbed? You may assume the neutron is not scattered. a)...

How does one determine/calculate the masses, orbital period, and separation of two merging neutron stars from the characteristics of its gravity wave LIGO signal? And how does this information allow one to calculate the distance to the galaxy that housed the merger? And how can one calculate...

Hi Point kinetics equation with one-group delayed neutrons, dn/dt= ((ρ-β)/∧)n+λC dC/dt= (β/Λ)n - λC When a reactor in steady-state operation, derivative terms would be zero. From second equation, C/n= β/λΛ is found. For given β=0.0065, λ=0.08 and Λ=0.0001, the ratio of the steady state...

Homework Statement Hi! So I stumbled upon this simple "plug n' play" exercise in my Physics textbook. Basically it gives you certain molecules/atoms, and tells you to measure the Electric Charge, and its Mass. Pretty simple, but I hit upon some hickups. Anyway, let's get to it: Find the...

Okay, as we all know, there's been a lot going on in the world of Astronomy and Astrophysics recently due to the collision of two Neutron Remnants. Personally refuse to call them "stars", because they are the remnants of proper stars and not proper stars in and of themselves. There have even...

Is there a theoretical limit to the size of neutron stars? It seems likely neutron stars are not simply electrons orbiting a proton so what is their life cycle? Can they just evaporate slowly by neutron decay?

Bear with me, I am just a chemist. Observations took several days (up to two weeks if memory serves me well). What I wonder is - why had different types of the EM radiation came at different times? Gamma burst was observed at almost exactly the same time gravitational waves were detected, but...

I have seen it claimed online that the recently announced observation of a neutron-star merger by LIGO provides strong support for the hypothesis that heavy elements - gold and platinum were mentioned in particular - are mostly created in neutron-star collisions rather than in supernovas. Is...

I have a sci-fi idea regarding being able to move planets around like billiard balls. I'm theorizing that, after a nova, some of the bands of material around a star formed a new ring of rocky planets around a Neutron Star. Naturally, these are bathed in radiation. Having never taken high...

A nucleon that consists entirely of two or more protons, would be accelerated evenly, as each proton would see the same force (barring any collisions or other extraneous events.) Each should experience the same force of repulsion or attraction that is causing them to accelerate, so they should...

what is the goldilocks range from a neutron star?

I read an article today stating that the possible explanation for the near total absence of heavier elements such as gold and uranium in many galaxies may be due to those galaxies not forming around a central black hole that has in absorbing one or more neutron stars causing fusion of neutrons...

Rumors are starting to fly that LIGO/VIRGO sees a signal of merging neutron stars, with an optical counterpart. Indeed, the thing that seems to have triggered the rumors was having a number of telescopes suddenly pointing at the same patch of sky. It's difficult to discuss the science behind...

Before today, I'd been led to believe that collections of only one (or few) types of matter could never exist: And to my surprise it is indeed possible to have degenerate matter, resulting from the death of less massive stars! So I'm curious: If these lesser massive stars collapse due to their...

new scientist July 15, 2017 current issue has article on boson stars, objects with the size and mass of stars, but composed of bosons. boson stars could mimic black holes. that got me thinking. if you had glueballs gravitational bound and the size and mass of a neutron star - or even larger -...

Hi there... I have a question about the tipical mass-radius relation plot for a neutron star, something that looks like this for different equations of state: My question is, what is exactly happening at the ends of the EOS lines? I know that after passing the maximum mass the curve starts...

This is more or less a question to which I think I know the answer to but want to make sure I'm right. So in light water reactors one of the safety features is that the light water coolant also serves as the neutron moderator slowing them down to the "thermal" range so that they can cause...

Just a quick question I got in my mind while reading up about fission, the so called Doppler effect which manifests itself in fertile material like U238, I read it helps control reactor stability , hence the majority of fuel consists of U238, as the fuel heats up at some point, U238 starts to...

If star start from a big ball of hidrogen and the all the neutron to make helium. Thx for help!

this is really basic I know but i would like to know if a neutron ,positron or alpha particle of a given energy will lose energy and velocity as it travels through space would atmospheric molecules have a significant effect as well on velocity/energy level. and if they do lose energy what form...

When two deuterons fuse, I understand they form an alpha particle in an excited state. Based on mass differences the fusion releases 23.85MeV, which is enough to eject a proton (19.81MeV) or a neutron (20.58MeV) from the alpha particle. It seems to prefer neutron emission, as this fusion is used...

When an artificial neutron source is created, from decay (from ground state or from an excited state resulting from fusion or a photon), or spallation, the trajectory of the emitted neutron is random,right? This would mean that there would be a neutron flux field, following the inverse square...

OK, I understand the idea of neutron bombardment of fissile material causing the nuclei of this material to split, thereby releasing more than 1 neutron, which then go on to bombard other nuclei, such that if more than 1 neutron per reaction ends up causing further reactions, the rate of...

Hi all, I've only just started studying nuclear physics so forgive me if this question makes no sense. I've read that the way neutron shielding works (in simple terms)is that the neutrons act as billiard balls by knocking into the shielding material atoms and being scattered like this until...