Death Throes of Red Supergiant Star Observed In Real Time (cnn.com) 47
"For the first time, astronomers were able to observe the death throes of a red supergiant star in real time," writes Slashdot reader quonset from a report via CNN. "The fortuitous event came about when astronomers were first alerted in the summer of 2020 by a release of bright radiation detected by the University of Hawaii Institute for Astronomy Pan-STARRS telescope on Maui's Haleakal. Then, In the fall, astronomers witnessed a supernova form in the same spot." From the report: Before they go out in a blaze of glory, some stars experience violent eruptions or release glowing hot layers of gas. Until astronomers witnessed this event, they believed that red supergiants were relatively quiet before exploding into a supernova or collapsing into a dense neutron star. Instead, scientists watched the star self-destruct in dramatic fashion before collapsing in a type II supernova. This star death is the rapid collapse and violent explosion of a massive star after it has burned through the hydrogen, helium and other elements in its core. All that remains is the star's iron, but iron can't fuse so the star will run out of energy. When that happens, the iron collapses and causes the supernova. A study detailing these findings published Thursday in The Astrophysical Journal.
"It's like watching a ticking time bomb," said senior study author Raffaella Margutti, an associate professor of astronomy and astrophysics at UC Berkeley, in a statement. "We've never confirmed such violent activity in a dying red supergiant star where we see it produce such a luminous emission, then collapse and combust, until now." Some of these massive stars likely experience consequential internal changes that cause the tumultuous release of gas before they die, the finding has shown.
"It's like watching a ticking time bomb," said senior study author Raffaella Margutti, an associate professor of astronomy and astrophysics at UC Berkeley, in a statement. "We've never confirmed such violent activity in a dying red supergiant star where we see it produce such a luminous emission, then collapse and combust, until now." Some of these massive stars likely experience consequential internal changes that cause the tumultuous release of gas before they die, the finding has shown.
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Re: the end(?) of another supergiant (Score:1)
Re: the end(?) of another supergiant (Score:3, Funny)
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Re: Failed prediction (Score:5, Informative)
why are sunspots (the deepest we can see into the sun) dark/black instead of blazing blue/white/red hot? They're actually blazing orange/red. They seem dark/black due to the surrounding brightness.
Re:Failed prediction (Score:5, Informative)
The same reason that the glass in one of those plasma ball lamps does not melt instantly when turned on. Temperature at times is a poor indicator of what is going on. So while the corona has a higher temperature than the surface of the Sun, due to the much lower density of matter the amount of heat energy per cubic metre in the corona is *much* lower than at the surface of the Sun. No laws of thermodynamics are being broken.
What astrophysicist's don't understand is exactly how the matter at the surface of the Sun is ejected into the corona. That is we don't have a good working model of how it works. The basics however are not in dispute some sort of electromagnetic process is going on to accelerate particles off the surface into the corona.
If you come up with a working model of how that happens there are a number of private fusion companies that would be very very interested to hear from you for $$$$. There will also be a Nobel prize for you.
Re:Failed prediction (Score:4, Informative)
If fusion reactions are heating the sun, then why is the sun's surface 10,000F while the Corona (made of plasma) 1000 miles up in the atmosphere 2 million degreesF?
What a bizarre argument. Fusion occurs in the core of the sun. When you get to the surface and the corona, the process heating the sun is thousands of miles deep, so it's basically irrelevant to how the corona and surface act. Whether it's fusion (which all real evidence says it is) or that there's a giant compost heap in there, or pixies flapping their wings hard, etc. it's just a source of heat from the perspective of the outside. The actual why of the corona being so hot is that it's heated by the same magnetodynamic forces that produce prominences. Basically, the corona is composed of particles that were super accelerated away from the surface.
Also, why are sunspots (the deepest we can see into the sun) dark/black instead of blazing blue/white/red hot?
This made me think that your posts may well just be parody rather than you being serious. I mean, the naivete required to believe that is staggering. It's like "jet fuel can't burn hot enough to melt steel" levels of ignorance and just generally not getting how stuff works. I mean, actually believing that sunspots are actually black rather than that you're just looking at an image where the slightly darker areas are mapped to black so they stand out? It really seems like no one could be that foolish and still be able to post.
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I remember, watching a partial eclipse of the Sun long ago through a pair of crossed polarizing filters. At the time, there was a sunspot that was large enough to be visible to the naked eye and it certainly looked black. Of course, I understand that it wasn't really black, but it didn't need any colour correction to stand out
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They're something like a third as bright. So that's a decent contrast, so they will look dark relative to the rest of the sun. There's obviously no digital manipulation when using your eyes, but there is manipulation, it's just all organic and analog. If you're looking at a digital image and the sunspots are represented with dark/black and the rest of the sun is bright, I'm not sure what to call that other than the colors being mapped.
Re:Failed prediction (Score:4, Informative)
I was wondering why anyone would write such retarded nonsense, but then I saw it was Anonymous Coward.
Well done.
This is one of the things that's pretty much well understood and predicted. We're all super happy that we actually get to SEE one.
Holy Crap! (Score:3, Informative)
This is apparently part of a crazy alternative physics [skeptoid.com] that I'd never heard of. The linked article and a few other pro sites are as far down the rabbit-hole as I care to go. It reads like flat Earth for people who want to sound a bit more intelligent, but are just as delusional. It's like reading something written by somebody who wanted to achieve the popularity of Velikovsky and failed.
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They're exactly like flat earthers, actually :D Probably the fun videos about it all are the debunk ones.
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Crazy alternative physics, such as that proposed by Nobel prize winning plasma physicist Hannes Alfven?
Most alternative physics has some basis in a discarded theory of real scientists. Cold fusion was, briefly, believed to be a real result by real experimental physicists and then demonstrated to be wrong. It's easy to build a fusion device at home [wikipedia.org] and there's still nothing that currently 100% rules out the possibility of cold fusion, based on some catalyst type structure with strong electric fields, however there's plenty of clear evidence that it isn't happening [wikipedia.org] in any of the situations described.
The fact that most slashdot'ers are unaware of such things reflects poorly on them.
This doesn
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Meanwhile, electric universe theory says that stars are primarily externally powered by galactic currents (birkeland currents) and can burn out like a fuse or light bulb when too much power runs through the circuit. So it predicts exactly this kind of event.
Really, does it? That's amazing. So, if you can just point us to where in the electric universe literature this prediction is actually made then I think the electric universe theory will have just gained some credibility. If there's no prediction like that in the literature, then it sounds like this is the typical act of painting the target around the bullet hole after the shot has been taken that electric universe enthusiasts usually partake in. I would say that would mean the theory has lost some credibil
Red Supergiant (Score:1, Offtopic)
Red supergiant? Something happened to Xi Jinping?
I want to know... (Score:2)
I want to know if LIGO saw anything.
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Yeah, I expect so, but:
https://astronomy.stackexchang... [stackexchange.com]
Unless the star is quite symmetrical, it could produce GWs.
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This is probably true. However, for all its incredible precision and sensitivity, LIGO can only spot the waves from much, much more energetic phenomena: the merger of of objects [google.com] with several-to-dozens of stellar masses apiece. The rapid mutual orbits of two stellar-mass objects represent huge displacements and accelerations, creating waves of detectable amplitude. The asymmetric wobbles of a single large star almost certainly do not register, u
Not the first time ... (Score:4, Informative)
Not the first by nearly a millenium. The Crab Nebula supernova was observed by Chinese astronomers in 1054. Wikipedia article https://en.wikipedia.org/wiki/... [wikipedia.org].
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The Chinese astronomers didn't have telescopes. So beyond seeing a bright spot in the sky with mark one eyeballs they didn't make the sort of detailed useful observations that have been made in this instance.
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The Chinese astronomers didn't have telescopes. So beyond seeing a bright spot in the sky with mark one eyeballs they didn't make the sort of detailed useful observations that have been made in this instance.
The formulation of 'real time' is silly in both cases anyway. The event happened long time ago. The real interesting part is this: if you consider the 'real time' thing in relation to when the light came to us then the actual observation by Chinese 1000ya were done in real time as they observed the light coming in as it passed the earth. What they did in Hawaii is difficult to say as the article in question does not provide such details. but chances are they were making photos and analyzing these with compu
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Were they observing the star that went supernova before it blew? That's what is different with these observations. Seeing supernovas is pretty common with today's telescopes as somewhere one is usually happening, even if billions of light years away.
In real time?! (Score:3, Insightful)
the star at the heart of this new research, located in the NGC 5731 galaxy about 120 million light-years away from Earth
This happened 120 million years ago!
Headline a little too sensational (Score:5, Informative)
The paper is here; https://iopscience.iop.org/art... [iop.org]
This star is very far away of course. It got brighter in the summer of 2020. Then in the fall it went supernova and they got spectrographic data, which showed that there had been large mass ejections beforehand. Apparently this had not previously been seen or expected in a star that size.
"symmetric emission lines that resulted from the photoionization of circumstellar material (CSM) shed in progenitor mass-loss episodes before explosion. Surprisingly, this novel display of pre-SN emission and associated mass loss occurred in a red supergiant (RSG) progenitor with zero-age main-sequence mass of only 10–12 Me"
This part is kind of interesting;
"ejection of stellar material following energy disposition into the stellar envelope as a result of gravity waves emitted during either neon/oxygen burning or a nuclear flash from silicon combustion."
Re: Headline a little too sensational (Score:1)
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I don't understand that either, maybe someone more knowledgeable can explain.
The term "silicon combustion" surely means that it is fusing, not burning in the usual sense of the word? But I have seen astronomers use that term in several places, maybe its just convenient.
As I understand it, the latter stages of the stellar lifecycle can be pretty quick. It takes a long time to fuse the hydrogen into helium in the core, but progressively less time to generate and fuse through the heavier elements. Towards the
"Real Time" (Score:2)
No it's not. Unless you're orbiting that star. And even then it's just close to real time.
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You demonstrate a misunderstanding of "Real-Time". It doesn't mean that you are seeing something with no time delay due to the travel of light/radiation, it means that you see the event unfold in the amount of time and the order that it actually happened. Don't be a dumbass.
Photos / Video (Score:1)
... or it didn't happen!