Hot answers tagged supernova
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There are lots of possible ways that stars can end their life, even in the subset of cases where the end is violent. @Eloff has given an excellent answer, but I wanted to add a few points.
Summary (tl;dr):
You need the right conditions (mass, angular momentum, metallicity, etc) to produce a proto-neutron-star which is able to resist complete collapse to a ...
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The calculation is done for 1987A here. Basically, the neutrinos' fractional speed increase from the new paper is $2.48\pm0.28\pm0.30\times10^{-5}$ (statistical / systematic errors, respectively) . SN1987a was $166\,912\pm10.1$ ly away, so multiplying the fraction by the travel time gives $4.14\pm0.97$ years. In reality, we got the neutrinos a few hours ...
12
None of those stars can go supernova, so the question is rather moot. If you look at the classifications, the most luminous is Sirius A (an A sequence star even) you can get an idea of its mass. If you look at your source page, and link to the explanation you see that A stars range from 1.4 to 2.1 stellar masses. In order to go supernova though, you need ...
10
Depends on the detection technology.
Yes
Cerenkov based detectors (SNO and Super-Kamiokande for instance, as well a many cosmic ray neutrino detector) are direction sensitive, and this is one of the design considerations that drive the use of this tricky technique. The best results come from quasi-elastic reactions like $\nu_l + n \to l^- + p$.
The ...
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You have to run a massively sophisticated supernova simulation to get that kind of data. Whole research groups work on them. The biggest unknowns are generally the details of neutrino physics. This is both because neutrino hard data doesn't come easy, and because solving the radiation field of a supernova is a function of seven or eight variables (x, y, z ...
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The biggest thing about this supernova is how CLOSE it is. A mere 21 million light years away (as opposed to being a billion light years away). The folks at John Hopkins think that studying a ype Ia supernova is valuable for several reasons.
SNe Ia are also very bright compared to other standard candles, which means they can be seen at high redshifts ...
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You're correct that when fusion reactions decrease past a certain point because the fuel is used up, the outward pressure created by the fusion no longer counteracts the gravitational forces and the star collapses (rapidly) in on itself. In stars of the right mass (smaller than about 15 solar masses, but large enough to collapse into a neutron star) the ...
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In answer to your question of "What happens to the neighboring star?", according to the John Hopkins folks, it gets blown away:
(Credit John Hopkins)
I would be a little skeptical of the certainty of this claim only because we have not been able to observe any of these Type Ia explosions up close while it is happening. That's why the Type Ia PTF 11kly is ...
7
The short answer is probably "yes we can", and possibly "we've already seen supernovae from the first galaxies", in the form of long-duration gamma-ray bursts. GRB 090429B has been given a redshift z=9.4, beating the previous record-holder GRB 090423 at z=8.2. As we continue to watch the skies, we're seeing more and more of these objects, and we'll gradually ...
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Be careful when trying to intuit how sensitive the integral formulation is to changes in $w$. The equation of state parameter only enters as part of the exponent of $1+z$, so for $z \approx 0$, $w$ has approximately no effect: $1^0 \approx 1^\epsilon$.
To illustrate with equations, suppose you already know $\Omega_\mathrm{M}$ and $\Omega_\mathrm{DE}$ ...
5
You can fit a value for Dark Energy (DE) using near or far supernovae (SNe), the benefit of distant SNe is purely from a statistics perspective: you want to minimize your errors on your best fit value of DE ($\Omega_{DE}$). To determine the uncertainty in your fit ($\sigma_{\Omega_{DE}}$) you have to do error propagation which will show a dependence on the ...
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I'm not an expert in stellar physics by any means, but I can say this: the velocity discrepancy observed by OPERA, $\frac{v - c}{c} = 2.9\times 10^{-5}$, would correspond to a delay ("prelay"?) of around 4 years for neutrinos coming from SN1987A. The observed delay was only 3 hours, which is smaller by a factor of roughly ten thousand. So if you assume that ...
5
A Type Ia supernova is different from many others because of the extremely close similarity of the circumstances leading up to it. First you begin with a white-dwarf star which is composed of the Carbon and Oxygen remnant core of a former main sequence star under extreme pressures and held up by electron degeneracy pressure. A white-dwarf which happens to be ...
5
Dr Phil Plait covers the effects of a supernova near a habited planet extensively in his book Death from the Skies. Basically, it would have to happen at a distance closer than 25 light years. Given that constraint, and looking at our system, no stars are candidates for a supernova explosion that would wipe us out. A GRB is a different beast entirely, and ...
5
Is it possible to estimate? Yes. I'll give it a quick try. But the details of whether the planet will be incinerated and so on will make the reality much more complicated.
As a ballpark, I think supernovae release about $10^{53}$ erg of energy. Spread over a sphere of, say, 1 AU gives $3.55\times10^{22}$J.m$^{-2}$. This energy isn't all released in one go ...
4
Diehl et al. (2006) used gamma ray observations to map $^{16}$Al in the galaxy. Because $^{16}$Al has a half-life long compared to the expected rate of supernova, but not so long we expect the SN rate in the galaxy to have changed dramatically over that time, it might be an indicator of the recent SN rate. Actually carrying through this calculation relies on ...
4
There is the ground based observatory ( nice picture) Veritas.
VERITAS (Very Energetic Radiation Imaging Telescope Array System) is a major ground-based gamma-ray observatory located at the basecamp of the Fred Lawrence Whipple Observatory in southern Arizona, designed to observe and study very-high-energy (VHE) gamma-rays (energies above ~100 GeV).
...
4
Their angular momentum stays nearly constant. You might be thinking of their angular velocity.
There is a lot of simulation-based work out there on the inspiral of two compact supernova remnants (NSs or BHs), done partly to determine what the gravitational wave signals would look like for the LIGO experiment. Two NSs would merge to form a BH, because their ...
4
Good question. I have a vague idea about how errors like this are catered for so I'll take a shot at answering your question. I stand to be corrected by anyone who's closer to SNe Ia cosmology. The short answer is that the discovery of dark energy is based on empirical calibrations, so any scatter in the progenitors of the supernovae is already accommodated.
...
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I'm not sure all the details of the Solar System formation are understood, but the general principles are well established. The dust cloud from which the Solar System formed was probably roughly homogenous. However once the Sun began to form, the dust cloud around it rapidly became differentiated. The heavier non-volatile elements stayed near the Sun while ...
3
Supernovae can release several times 10^44 J of energy. This has resulted in the adoption of the foe (10^44 J) as the standard unit of energy in the study of supernovae.
The Foe is a unit of energy equal to 10^44 joules.
To measure the vast amounts of energy that produces a supernova, the scientists used a unit of energy occasionally called foe was an ...
3
If you're asking about the duration of the explosion of supernovae, then it's done within a few seconds (the number can still be less) - similar to a nuclear fission. But, the cloud surrounding the explosion (i.e) the matter remnant that is thrown off can still remain expanding for years and it can emit EM radiation in the form of $\gamma$-rays and X-rays ...
3
Supernovae can take well over a week to reach maximum luminosity, and they stay rather bright for months after the peak. This just goes to show how much energy is involved in these event.
I was going to assemble a collage of light curves from my own research, but then I realized this has already been done at Wikimedia Commons:
These are rather idealized ...
2
First, check this reference on Wikipedia.
Now, it is generally true that the "speed" (or, more accurately, the dispersion relation) of any particle is affected by a medium, where it travels. Well, of course, if the particle interacts with the medium.
For neutrinos the "slowing down" itself is absolutely negligible even in very dense media. What is ...
2
When the matter of the Ni/Fe core collapses, it releases huge amounts of energy in the form of radiation as well as high energy jets (ejected from the rotational poles of the black hole), so a lot of the mass + energy the black hole is trying to engulf (and keep for itself) is actually escaping before being trapped in the black hole.
Also, do not be ...
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