Powerful Supernova May Be Related To Death Spasms of First Stars

necro81 writes "The New York Times is reporting on a discovery from a team of UC Berkley researchers, who may have discovered the brightest stellar explosion ever observed. Observations of the cataclysmic explosion of a 100- to 200-solar-mass star began last September, based on data from the Chandra X-ray Observatory. The researchers believe that the explosion is similar to the death spasms of the first stars in the universe. The super-massive star's collapse is believed to have been so energetic as to create unstable electron-positron pairs that tore the star apart before it could collapse into a black hole — seeding the universe with heavier elements."

Re:Time-lapse video?

[ls -la]

As far as I can tell from the articles, most of the observation was through means other than the optical spectrum pictures you're looking for (e.g. x-ray and IR pictures, spectroscopy, etc.). In fact, this supernova was so far away (240 million light years) that I'm not sure they could see it through optical telescopes. Most of a supernova's radiation (especially in something this violent) is emitted in the gamma ray range.

Here's the NASA page.

[u-bend]

Here's the NASA article about it. [nasa.gov]

Re:Eta Carinae

[Jugalator]

It's not too bad unless we'd be unlucky and have a gamma radiation burst from it heading towards us.
From here [freeinternetpress.com]:

The potential danger comes from the fact that explosions of massive stars generally emit jets of intense gamma radiation, among the most powerful and harmful forces in the universe. If Eta Carinae did explode and a jet was pointed in the general direction of the solar system, Livio said, Earth could be endangered. But because the gamma-ray jets tend to be relatively narrow, like the beam of a lighthouse, the odds are that the jet would miss Earth.

So it's not too bad, it would probably just miss us.

:-/

Re:we should we believe the astrophysicists now?

[Red Flayer]

Just goes to show you the arrogance of physicists- they claim answers and grandiose Standard Theories, but are frequently revising them because they mis things like accelerating expansion and 150SM supernova.

Right. So we should not put blind faith in any theory, because it's open to being falsified. That's basic scientific method stuff.

Isn't this what academic research is (in theory) all about? The search for better understanding, enabling us to revise our theories of how the universe (or some small subset of it) works?

Find the simplest theory that fits all the observations. New data may mean you need a new theory, or that you need to revise your current theory. I don't understand the problem you have, unless it's just with the arrogance of some theorists who claim to have found the answer to Life, the Universe, and Everything. I say, let them be arrogant -- when they are disproved, they'll fall harder for it.

Re:Actually, it's T E X A S

[MontyApollo]

From the article:

The discovery was made by Robert Quimby, a University of Texas graduate student, who was using a small robotic telescope at McDonald Observatory near Fort Davis, Tex., to troll for supernovas

Re:Oddity

[ls -la]

I guess they should say "might see if it went supernova soon."

We know information cannot travel faster than the speed of light (or if you prefer, cannot reach outside the light-cone [wikipedia.org] of the event). So if an event "happens" 7500 light years away, did it really happen before the light reaches us? In some sense, an event has not happened until we are inside its light-cone.
Perhaps it "happens" when its light-cone intersects ours? The question with this interpretation is, where does our light-cone start?

Time is relative, and over distances of at least the order of a light second (186,000+ miles), it is difficult to think about correctly.

Re:Eta Carinae

[vrmlguy]

First, Eta Carinae is not visible to anyone north of 27 N, so in the US only people in or south of Miami will see it. In Africa, you basically have to be in a country that doesn't touch the Mediterranean Sea; while in Asia every country touching the Indian Ocean will see it, but not China or Japan. Among English-speaking countries, only Austrailia will have a great view, but the ozone layer will protect them (and the rest of the Southern Hemisphere) from direct radiation. "Scientists at NASA and Kansas University have determined that the supernova would need to be within 26 light years from Earth to significantly damage the ozone layer and allow cancer-causing ultraviolet radiation to saturate the Earth's surface. An encounter with a supernova that close only happens at a rate of about once in 670 million years(...) The new calculations are based largely on advances in atmospheric modeling, analysis of gamma rays produced by a supernova in 1987 called SN1987a, and a better understanding of galactic supernova locations and rates. A supernova is an explosion of a star at least twice as massive as our Sun." [nasa.gov] Since Eta Carinae is 300 times that distance, its blast wound need to be 90,000 times as energetic to be dangerous. A hypernova is about 100 times more powerful than a supernova, so there's plenty of margin of safety there.

Re:Oddity

[Orange Crush]

There is no such thing as synchronicity in this universe. Cause travels at the speed of light (or slower), gravity and relative velocity alter time and quantum states are ambiguous until observed. That star has a high probability of already having gone supernova, but this is meaningless in our frame of reference until the event is observable.

Re:Kinda OT, but I thought I'd say...

[BlackSnake112]

"University of Texas graduate student Robert Quimby first observed the supernova on Sept. 18, 2006 in the galaxy NGC 1260, located in the constellation Perseus. Filippenko's team immediately began observing it with its dedicated supernova search and monitor telescope at Lick, the Katzman Automatic Imaging Telescope." They did, if you RTFA

Re:Time-lapse video?

[$RANDOMLUSER]

Indeed. The best images are from the Chandra [harvard.edu] X-ray observatory. They have some animations here [harvard.edu].

Re:Time-lapse video?

[p_trekkie]

Most of a supernova's radiation (especially in something this violent) is emitted in the gamma ray range.

Actually, most of the radiation comes out as neutrinos. Only 1% comes out in forms we can detect at all...

Re:Here's the NASA page.

[john83]

Here's the paper about it [arxiv.org].

From the abstract:
We report our discovery and early observations of the peculiar Type IIn supernova SN 2006gy... It is not yet clear what powers the enormous luminosity ... but we argue that any known mechanism ... requires a very massive progenitor star... SN 2006gy is the first supernova for which we have good reason to suspect a pair-instability explosion... SN 2006gy also suggests that the most massive stars can create brilliant supernovae instead of dying ignominious deaths through direct collapse to a black hole. If such a fate is common among the most massive stars, then supernovae from Population III stars in the early universe will be more numerous than previously believed.

Interesting stuff!

Re:heavy elements

[stewardwildcat]

http://en.wikipedia.org/wiki/Nucleosynthesis [wikipedia.org] its called nucleosynthesis. The reaction chains that fuse in the sun are called nuclear reaction networks. There is a lot of information available on this but Wikipedia gives a nice overview./

Re:heavy elements

[navyjeff]

I would start with a chart of nuclides [bnl.gov] and a chart of the current model of subatomic particles [particleadventure.org] to investigate the chain of fusions and fission.

I hope you like physics, though. The chart of nuclides can be a bit confusing at first.

Re:Oddity

[linzeal]

Also known as, Minkowski Space [wikipedia.org].

Re:Eta Carinae

[georgewilliamherbert]

Pair creation supernovae were predicted decades ago. The conditions for their formation are a bit strict and they do not appear to be very common at this point. Black hole creation is probably must more common.

If you neglect angular momentum (i.e., for only moderately rotating stars), the current predictions are that pair creation supernovae are the normal mechanism for stars with a low metalicity and immediately pre-supernova mass from about 140 to about 260 solar masses. If you look at the webpage in the summary http://astro.berkeley.edu/~soffner/imgsf8.html [berkeley.edu] it shows the metalicity / mass behavior estimates. Also see http://www.ucolick.org/~alex/firststars/ [ucolick.org], particularly the diagram at the bottom. It shows the no angular momentum low metalicity stellar behavior: 8-25 Solar Masses, you get a neutron star. 25-50ish, you get a neutron star that then reabsorbs enough of the source star's mass via fallback to become a black hole. 50-100, you get a direct collapse to a black hole. From 100 to 130 solar masses, the pair production mechanism kicks in and pulses a few times, ejecting mass, and then it falls below 100 SM from the ejections and should collapse to a black hole on the next pulse. From 130 or 140 up to about 250 or 260 (depends on whose paper/numbers), pair production doesn't pulse, it goes bang, and the explosion generates enough energy to gravitationally unbind the whole star (blow it completely apart, no or little remnant). Above the 250/260 point, they predict that pair production happens but it just direct collapses essentially the whole star to a black hole, not fusions off to explosion as in the slightly smaller ones.

Re:Time-lapse video?

[p_trekkie]

Type I versus Type II

A fundamental difference between Type I and Type II supernovae is the source of energy for the radiation emitted near the peak of the light curve. The progenitors of Type II supernovae are stars with extended envelopes that can attain a degree of transparency with a relatively small amount of expansion. Most of the energy powering the emission at peak light is derived from the shock wave that heats and ejects the envelope.[57]

The progenitors of Type I supernovae, on the other hand, are compact objects, much smaller (but more massive) than the Sun, that must expand (and therefore cool) enormously before becoming transparent. Heat from the explosion is dissipated in the expansion and is not available for light production. The radiation emitted by Type I supernovae is thus entirely attributable to the decay of radionuclides produced in the explosion; principally nickel-56 (with a half-life of 6.1 days) and its daughter cobalt-56 (with a half-life of 77 days). Gamma rays emitted during this nuclear decay are absorbed by the ejected material, heating it to incandescence.

As the material ejected by a Type II supernova expands and cools, radioactive decay eventually takes over as the main energy source for light emission in this case also. A bright Type Ia supernova may expel 0.5-1.0 solar masses of nickel-56,[58] while a Type Ib, Ic or Type II supernova probably ejects closer to 0.1 solar mass of nickel-56.

Thanks in advance for advancing my understanding. Apologies if there is anything akin to an apples/oranges misunderstanding at the base of my query...

The answer lies in whether you count neutrinos as radiation or not. What I should have stated in my original post was that the vast majority of the energy released in supernoave comes out in the form of neutrinos, which we have a really really hard time detecting...

Wikipedia is correct as to the source of photons that we detect. I counted neutrinos as a form of radiation in my earlier statement (since in my mind, that's what they effectively are), but neutrinos are not photons. Hence, there is no discrepancy. Basically, when we take the energy difference between the potential energy of a star before and after a Type II SNa (like this one) and check that against the energy we see from photons, we are only seeing 1% of the energy that should be coming out in all forms of light. The rest of the energy is believed to escape in the form of neutrinos.

Re:Time-lapse video?

[imsabbel]

Also:
"
The core implodes at velocities reaching 70,000 km/s (0.23c),[40] resulting in a rapid increase in temperature and density. Through photodissociation, gamma rays decompose the iron into helium nuclei and free neutrons. The conditions also cause electrons and protons to merge through inverse beta decay, producing neutrons and electron neutrinos. About 1046 joules of gravitational energy are converted into a ten-second burst of neutrinos.[41] These carry away energy from the core and accelerate the collapse, while some neutrinos are absorbed by the star's outer layers and begin the supernova explosion.[42]

The inner core eventually reaches a density comparable to that of an atomic nucleus, where the collapse is halted. The infalling matter then rebounds, producing a shock wave that propagates outward. This expanding shock can stall in the outer core as energy is lost through the dissociation of heavy elements. However, through a process that is not clearly understood, the shock reabsorbs 1044 Joules[a] (1 foe) of energy, producing an explosion.[43]"

You might have stumbled upon this part of the article while getting to the part you quoted. 10^44 joule ->explosion, 10^46 joule -> neutrino burst.
->only 1% is visible.

Re:E.L.E

[Frozen Void]

Its not so clear.
1.It depends on how much matter is dispersed between us and the supernova(plasma,dust,stars,etc)
2.The estimate of mass and star composition are correct.
3.The mechanism of supernova production is well understood.(not really:the electron-positron pair supernova is new)
4.GRB angle.

http://en.wikipedia.org/wiki/SN_2006gy [wikipedia.org]
Similarity to Eta Carinae

Eta Carinae ( Carinae or Car) is a highly luminous hypergiant star located approximately 7,500 light years from Earth in the Milky Way galaxy. It is estimated to be similar in size to the star which became SN2006gy. Dave Pooley, one of the discoverers of SN2006gy, says that if Eta Carinae exploded in a similar fashion, it would be bright enough that one could read by its light. However, Pooley estimates the likelihood of the star exploding in the near future as small, with a minimal risk to life on Earth.[4]