Questions tagged [neutron-star]

Questions regarding a degenerate star that is mainly composed of neutrons.

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Is the smaller companion of Pulsar J0453+1559 still the smallest known neutron star? Was it further confirmed to be a NS after Martinez et al. (2015)?

@ProfRob's Physics SE answer to What is the theoretical lower mass limit for a gravitationally stable neutron star? was linked just now in their answer to Can a neutron star ever be less than about 1....
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What escape velocity would quark stars have?

Quark stars are hypothetical compact stars that are denser than neutron stars and maybe the last stage of upholding matter before stars that collapse into a singularity. Neutron stars have escape ...
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Can a neutron star ever be less than about 1.44 solar masses (the Chandrasekhar limit)? Why not?

I learned about the Chandrasekhar limit as being the UPPER limit, in terms of mass, for a white dwarf... But, I have never heard of a neutron star being BELOW that mass, so I have wondered, recently, ...
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Is there anything different about the gravitation around a non-spinning black hole and a neutron star of the same mass?

If we perform a simple experiment by orbiting identical spacecraft around a non-rotating black hole and a non-rotating neutron star of equal mass at a "safe" distance, and ignore differences ...
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Is something wrong with my luminosity calculation?

A few million years after a white dwarf forms, its surface temperature reaches $100000\text{K}$, while its radius is $0.01R_\odot$. Would this mean that its luminosity is $\Big(\dfrac{100000}{5778}\...
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Strange matter objects other than neutron stars?

This question is about celestrial objects which are composed by exotic matter, and exotic matter I define as states of matter that are not commonly encountered such as Bose–Einstein condensates, ...
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Are there any known neutron star - supergiant binaries?

After looking for more information about TZOs (Thorne-Zytkow Object), I came up with a question that I had trouble finding answers on the Internet. Do we know of any future TZOs, supergiants being ...
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Can a Thorne-Żytkow object be the progenitor of a modern quasi-star?

I was reading some Wikipedia articles about astronomy, and came across an interesting line: The neutron star may also accrete sufficient material to collapse into a black hole. Now, here is my ...
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Can mass loss via accretion occur on stellar remnants?

We know that normal stars can lose mass to a binary companion. But can this happen to neutron stars and white dwarfs? Let's say a stellar black hole is being orbited by a white dwarf or neutron star. ...
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What would happen if a neutron star merged with a white dwarf?

We've heard of neutron star mergers and white dwarf mergers. But what would result in a neutron star merging with a white dwarf? Would there be a similar super/kilonova, are there any examples of it, ...
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Can a star be massive enough to go 'supernova' yet not be massive enough to leave behind a neutron star? Or, perhaps vice versa?

From what I understand, stars that explode as a supernova at the end of their lives become either a black hole or a neutron star, and less massive stars that do not explode become white dwarves, but......
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The star that died and became the Crab Nebula and Crab Pulsar?

The supernova of this star was witnessed about 1 thousand years ago, and the star's remains are the Crab Nebula and Crab Pulsar. What is this no longer existent star called? How massive was this star? ...
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Stellar life cycle flow chart with mass conditions and time scales

I remember that in my nuclear astrophysics lecture a decade ago, our lecturer drew a large flow chart like diagram of stellar evolution in dependence of the mass of the star (in solar units) on the ...
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What about the magnetic field strength inside of an old accreting neutron star?

As the magnetic field strength outside an old accreting neutron star is thought to be small (about $10^8-10^{10}$ Gauss), what about it inside the star? Because of the superconductivity and ...
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What is the gravitational wave spectrum of an ellipsoid neutron star like?

If the star is ellipsoid instead a sphere, the wave should be rich of harmonics, not only (2*orbital frequency). Can these harmonics behave the same way, i.e. they appear/disappear together and drift (...
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How big would the supernova when a neutron star collides with another neutron star? [closed]

If two neutrons stars that are orbiting were to collide, how big would the supernova explosion be? Would a new black hole or a new supernova remnant be formed?
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Question about redshift and effective gravity at the rotating neutron star surface

For a rapidly rotating neutron star, if consider the star as a sphere, redshift at the equator surface will be larger than at the pole. But if consider the star as an obsolate sphereiod (the ellipsoid ...
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Do neutron stars have an ergosphere?

Ergospheres are a property of black holes, and do neutron stars have it? If yes, why seldom article mentions that; if no, why can't neutron stars have this ergosphere component?
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How could we search for old cold neutron stars?

This is the inverse of Will Gaia detect inactive neutron stars? (to which the answer was "probably not"). So if Gaia can't do it, what would it take? How could such a search work, and what ...
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Assuming proton decay is false, what's the ultimate fate of a neutron star or white dwarf?

A still unproven theory that protons can decay, and have a halflife of $10^{30}$ years or so, meaning eventually all matter will dissolve because their constituent protons and therefore neutrons will ...
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660 views

Is nuclear pasta or neutron star crust iron stable outside of neutron stars?

When neutron stars collide, they crash into and kill each other in a kilonova explosion, which blasts a lot of their material into space. A huge amount of neutronium, neutron star stuff, is suddenly ...
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Is there a Vela Nebula?

The Vela pulsar is a neutron star from a supernova that exploded 10,000 years ago. It spins 11 times a second. The Crab Nebula along with the central Crab Pulsar formed 1000 years ago. This pulsar ...
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How did Fermi manage to see neutron star merger?

When the GW170817 neutron stars merger was observed by LIGO/Virgo, the Fermi gamma-ray telescope observed the event 2s after the merge. How did it know where and when to look? It must take some time ...
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Why do objects appear blue while on a neutron star?

I was playing around in Space Engine recently, and I realized I hadn't yet landed on a neutron star. This seemed like a very sensible thing to do, so I did it and chose a (relatively) well-known one ...
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Can a pulsar also be a magnetar?

I know this is a simplistic question, but I cannot find a straight answer... Also, is it possible most or all neutron stars are magnetars and/or pulsars? It's just hard to see all of their properties ...
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How likely are planets to form after neutron star collisions?

It is well known that planetary collisions can create moons orbiting the result of the merger if they happen in the correct way, and this is how the Earth's moon is believed to have been formed. See ...
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What methodology should be used to choose the correct model for origin of QPOs in X-ray astronomy?

In X-ray astronomy, quasi periodic oscillations (QPOs) are routinely shown by black hole and neutron star X-ray binary systems in their X-ray flux. Despite being strong and easily measurable signals, ...
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What would happen on earth if there was a surge in gravitational waves [duplicate]

There are claims that when massive objects merge some of their mass is converted to gravitational energy. Such as the following links: https://astronomy.stackexchange.com/a/38727/2305 https://youtu.be/...
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Fraction of initial mass lost (radiated) by neutron star mergers compared to black hole mergers?

GW190521 black hole merger total mass calculation and missing mass, how does this happen? notes that there are about 9 solar masses missing from the final black hole. GW170817 is the first observed ...
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Do the neutrons in neutron stars emit the radio waves?

Neutrons can, especially in extreme circumstances (and large concentrations) emit electromagnetic radiation. I specifically asked about this in Physics S.E. Has a free neutron ever been shown to ...
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How is angular momentum transferred between a neutron star and its accretion disk?

Accreting neutron stars can either gain or loose angular momentum via interaction with their accretion disks. This leads to either spin-up or spin-down. Which of the two is the case, depends on the ...
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If the sun is a second or third generation star, where is the neutron star? [duplicate]

It is widely believed that before the Sun was another star, more pristine in its composition (mostly Hydrogen and perhaps some Helium). And maybe before it was yet another. This blog explains this via ...
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Is there any synthetic spectrum software for neutron star?

Is there any software that can calculate the emergent spectrum of a neutron star photosphere, for Teff is about 1e7K, density is above 1e21-1e22 cm^-3 ? Output line wavelength is about 0-100A is ...
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Why can there be several seconds of lag between a binary neutron star merger and the emission of gamma rays from the same area?

Answers to: Gravitational waves and gamma ray burst: how were the error bars determined for this speed of gravity calculation? Was $H_0$ used? go into substantial detail explaining this determination. ...
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What is the “hypothesized lower mass gap” between 2.5 and 5 solar masses?

Searching here for "mass gap" yields nothing yet. Penn State's Black hole or neutron star? LIGO-Virgo scientists find mystery object in 'mass gap' begins: When the most massive stars die, ...
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Can the Sun contain degenerate matter?

Degenerate matter (neutronium) is hypothesized to be very dense and, at a certain amount, unstable - in the sense of collapsing on itself and causing fusion. The result would be a massive fusion ...
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Are there neutron stars whose magnetic axis and rotating axis are the same, and if so what will happen?

I know that there's probably a higher chance of having a neutron star that has its magnetic axis inclined to the rotational axis rather than having it perfectly aligned. If they are not aligned, the ...
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Is the object a pulsar

We have a star having 1.8 solar mass. Justify any four means (measurable/ observed properties) by which you can identify that the object is a Pulsar and not a white dwarf or a Black Hole. So one ...
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In practice, can very high magnetic fields significantly alter the dynamics of an astronomical-scale bodies?

The direct effect of magnetic fields on the dynamics (as in the movements, trajectories etc of the bodies themselves, rather than lower-level phenomena like stellar winds and atmospheric degradation) ...
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How far away are the events that caused the gravitational waves that have been detected?

A certain number of gravitational wave events have been detected. Is it possible to know how far away the mergers that caused those gravitational wave events are?
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Is the atmosphere of neutron star solid, liquid or gaseous state? [duplicate]

Neutron star has a thin layer of atmosphere consist mostly of hydrogen and helium and is about less than a metre thick on average, but what wasn't stated in many articles I read is the state of matter ...
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How does the field decay of a magnetar power the emission of high-energy electromagnetic radiation?

In Space.com's Dr. Pulsar and Mr. Magnetar? 2 Star Types May Turn into Each Other (and in the linked video) "Tom Prince, a physics professor at the California Institute of Technology and a senior ...
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Can we detect pulsars that aren't “pointed” towards us?

A pulsar is a highly magnetized rotating neutron star that emits beams of radiation through its magnetic poles, in the direction of the Earth. This makes it seem to pulse, as seen from Earth. There ...
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How can I hear (or at least detect) a pulsar at home?

Scott Manley's video Using Relativistic Raytracing &X-Rays To See Detail on Surface Of Neutron Star talks about X-ray measurements using the NICER X-ray telescope attached to the International ...
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If we accelerate a neutron star to move at speeds comparable to light would it become a blackhole because of the added energy?

Could a neutron star turn into a blackhole if it is accelerated to near luminal velocities? And if it slows down after a while, does it become a neutron star again?
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What is the “radiation sound speed” inside an accretion column?

I was trying to read "A New Two-fluid Radiation-hydrodynamical Model for X-Ray Pulsar Accretion Columns" and its follow-up paper both by West et al. and came across a quantity called "radiation sound ...
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Neutron star size in different reference frames

What is the estimated size of neutron stars observed in their reference frame and in our reference frame? That is, how bent is space-time around neutron stars?
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Could anything consume a small black hole?

Whenever I read about black holes, it is normally involving how they devour anything that comes too close... regardless of how big anything is. But what if it were a really small black hole vs ...
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Neutron star r-process nucleosynthesis

The $r$-process in supernovae happens when a high flux of neutrons irradiates the heaviest abundant nuclei (in the region of iron), resulting in endothermic nuclear reactions. To the extent that at ...