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35

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 ...


14

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 ...


13

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 ...


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 ...


9

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 ...


8

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 ...


8

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 ...


8

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 ...


8

How do I stay alive to be killed by neutrinos? You wouldn't. The point is being made that even the beam of neutrinos with a supernova at one astronomical unit distance would be intense enough that enough of them would interact with the matter of your body to be lethal. So even the neutrinos would get you if all the other stuff - notably $\gamma$s didn't. ...


7

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

It's interesting you found Tycho as an example as this was one of the early recorded supernovas back in 1572...by Tycho of course. This is considered a Type Ia Supernova and the image you reference isn't really how it looks. That's a modified composite to visualize the microwave and infrared components of the remains together. As Kyle mentioned, you can ...


6

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 ...


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

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

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 ...


5

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 ...


5

Here is the actual announcement of the redshift from Andrew Levan. For those unfamiliar with astronomy practices, circulars are generally where simple things like discoveries, first spectra, redshifts, etc. are announced just as soon as the data is gathered and a preliminary reduction is performed, usually issued the morning after the observation. In this ...


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

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. ...


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

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 ...


4

The time delay between neutrinos and photons does not tell us directly about the absolute mass of the neutrinos. The time delay between a neutrino of mass $m$ and a massless neutrino does: $$ \Delta t = \frac{d}{v} - \frac{d}{c} \approx 0.5 \left(\frac{mc^2}{E}\right)^2 d, $$ where $\Delta t$ is the time delay in seconds, $v \approx ...


4

http://profmattstrassler.com/2011/09/20/supernovas-and-neutrinos/ This website confirms what you said about the neutrinos from the 1987 supernova arriving before the light from the supernova. It doesn't specifically say which detectors detected the neutrinos. The reason the neutrinos reached earth before the light is not because the neutrinos were ...



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