Studying a star that survived a supernova-scale eruption

η Carinae has undergone a series of staggeringly large eruptions.

Read the whole story

 

[Molehill]

BatCrapCrazy[/url]":2jzy5ia6]Sigh why does all the cool stuff happen in the southern hemisphere?

Why for once can't something awesome happen up here in the northern hemisphere, like Betelgeuse (A.K.A. α Orionis, A.K.A. Alpha Orionis) go super/hypernova in my lifetime?

And to harp on like i do on every astronomical story that is posted:

I soooo miss my Meade 10" SCT with Bino-View.

Nothing in the article about this, and I don't know the distance, but on some level I'm happy to have the thing located with most of the Earth in between for when it goes off more dramatically.

 

[Sydde]

BatCrapCrazy[/url]":1xtkisi5]Sigh why does all the cool stuff happen in the southern hemisphere?

Yalongo, Warkworth, Paranal, Molonglo, Cerro Tololo, the Southern Hemisphere observatories just have better names.

 

[Korios]

dj__jg[/url]":hi6n02ko]

...m...[/url]":hi6n02ko]...i suggest writing 'eta' at least once in the article, since most lay readers aren't fluent in the greek alphabet and most popular material regarding eta carinae spells out its full name accordingly...

Although I am (sadly) familiar with the greek alphabet, I agree. Eta Carinae is way more common, and something that angry really deserves a full name

Why sadly??

 

[eldakka]

My theory is that eta Carinae is a weapons test site for an alien race. The bikini atoll of some alien race.

At the moment, they are testing ways to induce a supernova for weaponization.

 

[Korios]

Oak[/url]":2a0t15ki]
Why is that pretty likely to rule out a merger as the cause of the Great Eruption? Couldn't the merger have only happened in the 1840s (not dating literally of course, but speaking in terms of when the light reached us, as the article does), and before that, what is now η Carinae A were two death-spiralling stars?

That is, isn't something like the following possible?

Pre-1840 η Carinae A was two close stars gradually spiraling in to each other for centuries (I'll call "A1" and "A2") separated by a fraction of an AU. There could be some siphoning off of material from A2 to A1, causing asymetrical eruptions on A1.

(This siphoning would presumably be accelerated occasionally, when η Carinae B, in some of it's every-5.5-year passing within 1.6A of the pair, happened to line up, during that pass, with the line between the almost-merged pair, adding to the tidal stretching of them.)

Eventually, in the 1840s, A1 And A2 actually merged, creating a far great eruption.

(Imaginably that 5.5-year period and the 1.6 AU distance from B to the center of mass of the A1/A2 pair would vary somewhat, given the complex dynamics of a 3-body system where all 3 bodies have substantial mass relative to each other.)

(Not an expert, so anyone who knows more, feel free to poke holes.)

Because all current astrophysical models predict that if two huge stars merge they will collapse into a hypernova, and then into a quite large black hole. When two neutron stars merge they collapse into a supernova (and then into a black hole), and even when two white dwarves merge they go supernova (type Ia), with no black hole collapse. So, why didn't η Carinae collapse into a hypernova if it merged with a similarly big star?

 

[dj__jg]

Korios[/url]":18ipxtpu]

dj__jg[/url]":18ipxtpu]

...m...[/url]":18ipxtpu]...i suggest writing 'eta' at least once in the article, since most lay readers aren't fluent in the greek alphabet and most popular material regarding eta carinae spells out its full name accordingly...

Although I am (sadly) familiar with the greek alphabet, I agree. Eta Carinae is way more common, and something that angry really deserves a full name

Why sadly??

Greek was not my favorite subject. The 'highschool' I attend has it as a mandatory subject in year two and three, dropped it asap. Now I only have Latin as the bane of my existence. (Having at least one classical language is mandatory)

 

[iEvolution2]

[trollhide=Trolling.]

eldakka[/url]":3xkrln6d]My theory is that eta Carinae is a weapons test site for an alien race. The bikini atoll of some alien race.

At the moment, they are testing ways to induce a supernova for weaponization.

There is no such thing as supernova. It is a myth the scientists have been making it up all along to pay their salaries.

"Look, that tiny little bright spot at 10 o'clock is a supernova."

"There are lots of bright spots at 10 o'clock."

"No, no, no, listen dude, this one is a bit brighter than the two next to it."

Well, what can you say when you can't prove them wrong?[/trollhide]

 

[Hapticz]

in the scant time i have lived, to see, learn and enjoy, science has leaped beyond limits no religion could ever explain. while we may feel yet ignorant of the universe, the intricate dances that all this chemistry, energy and chaos perform, the grounding of our very existence relies upon accepting these dynamics that created life. we jump when we hear a gunshot, yet fail to respond to the literal concept of annihilation that would occur from these ordinary events that happen endlessly in the universe. so we think we can scoot off, somewhere safe some day, eh, Elon Musk??

 

[Nostromo21]

AzureMarquis[/url]":2geb20mg]"No star system will dare oppose the Emperor now."

The more you tighten your grip, AzureMarquis, the more star systems will slip through your fingers.

 

[Nostromo21]

Molehill[/url]":2w56mspc]
Nothing in the article about this, and I don't know the distance, but on some level I'm happy to have the thing located with most of the Earth in between for when it goes off more dramatically.

Eta Car is 7500 lys from us. So, for all intents & practical purposes, we will never get anywhere near it. Unless someone actually finally invents a working wormhole generator or some form of hyper/sub-space or teleport sci-fi drive!

Current state of astrophysics makes it quite clear that we will never get to any star, even our closest Proxima Centauri, with either current, or any imaginable reaction drives (including nuclear/antimatter). The amount of fuel mass required to get anywhere in any reasonable timeframe (short of generational ships flying for millennia) is simply too long.

 

[Nostromo21]

Hapticz[/url]":1hof6uei]in the scant time i have lived, to see, learn and enjoy, science has leaped beyond limits no religion could ever explain. while we may feel yet ignorant of the universe, the intricate dances that all this chemistry, energy and chaos perform, the grounding of our very existence relies upon accepting these dynamics that created life. we jump when we hear a gunshot, yet fail to respond to the literal concept of annihilation that would occur from these ordinary events that happen endlessly in the universe. so we think we can scoot off, somewhere safe some day, eh, Elon Musk??

"I find your lack of faith disturbing".

But seriously, your theological shortcomings aside, even if we could get out of our solar system, the effects we may experience leaving Sol's sphere of influence, not to mention the debris we would need to safely circumnavigate or shield a ship against somehow, at the required speeds, is simply mind-boggling. And who knows what lies between the outer reaches of the solar system in inter-stellar space? Maybe micro black holes are actually plentiful in deep space; maybe dark matter is in fact everywhere & plentiful outside of star systems & would impede reaching high velocities of any kind; or perhaps God created our entire solar system ala Peter Hamilton's Dyson Pair Enclosure in the Commonwealth Saga (the Truman Show in space!), and all of space is but a stage...? Ok, I don't really believe that's possible, but then again, who knows? Perhaps we will find more interesting things on Jupiter's or Saturn's moons one day *sigh*...

 

[FreeDemo]

iEvolution2 wrote:
There is no such thing as supernova. It is a myth the scientists have been making it up all along to pay their salaries.

"Look, that tiny little bright spot at 10 o'clock is a supernova."

"There are lots of bright spots at 10 o'clock."

"No, no, no, listen dude, this one is a bit brighter than the two next to it."

Well, what can you say when you can't prove them wrong?

Not just for the supernova. Also there are many unexplainable events happening in our universe that was nothing but guessing from the scientists with their high tech equipments and granted it is what it is without proof. This is how the science world works at this moment.

 

[Router66]

Just checked in wikipedia for this star and... my, oh my! It seems that this star/binary system is even emitting UV laser beams! I mean, all things considered and in all seriousness... W.T.F.?

Thanks John. Right up this moment I 've never even imagined that there's such a thing as a solar laser. If I may, I suggest you set up a monthly column of "extraordinary things in the sky" or something similar. It's not just about feeding the greed of arsies for the spectacular and the unusual. The new generation of huge telescopes will, presumably, have these spectacular objects as prime targets, so it 'll be nice if we knew a couple of things about them beforehand.

 

[kkeane]

Nostromo21[/url]":28tl5vru]And who knows what lies between the outer reaches of the solar system in inter-stellar space? Maybe micro black holes are actually plentiful in deep space; maybe dark matter is in fact everywhere & plentiful outside of star systems & would impede reaching high velocities of any kind

We can pretty much rule out plentiful micro black holes. If they were plentiful, they would absorb most starlight, and we would not be able to see many stars.

Dark matter can't be everywhere, either. In fact, if it was everywhere, we wouldn't even have realized that dark matter must exist. We have a pretty good idea of where it is because we can see its gravitational effects.

Dark energy - that's another matter, though. That could be evenly distributed. But we aren't certain that it really exists; there are other possible explanations for the way the universe expands.

 

[Potatoswatter]

kkeane[/url]":3tbiir7x]We can pretty much rule out plentiful micro black holes. If they were plentiful, they would absorb most starlight, and we would not be able to see many stars.

There's no size of black hole that literally looks black and absorbs starlight. Microscopic black holes are excluded because we'd occasionally see them evaporating. Merely "small" black holes are excluded because they'd emit enough x-rays to be seen.

My favorite dark matter theory is black holes of about 30 solar masses, which would be too small for microlensing surveys and too uncommon for x-ray surveys.

Dark matter can't be everywhere, either. In fact, if it was everywhere, we wouldn't even have realized that dark matter must exist. We have a pretty good idea of where it is because we can see its gravitational effects.

It's everywhere inside galactic neighborhoods. The question is whether it's everywhere like neutrinos are everywhere. Maybe, maybe not.

Dark energy - that's another matter, though. That could be evenly distributed. But we aren't certain that it really exists; there are other possible explanations for the way the universe expands.

Dark energy is simply the energy associated with the expansion of the universe. It's contradictory to admit that the universe is expanding but to question that dark energy exists. Whatever your theory for how or why expansion is happening, that is also your theory of dark energy. At present, the Lambda-CDM model is most popular, which says that acceleration is due to a metric expansion of space. But there's no evidence for or against expansion at less than intergalactic scales, and any theory can equally seek to explain dark energy and expansion.

 

[markbanang]

Given the modern use of the word trolling, an Oxford dictionaries blog What is the difference between ‘troll’ and ‘trawl’? recommends using trawling on the internet:

Spoiler

The words are interchangeable in most circumstances; you could either troll the library or trawl the library in your search for a specific book. However, you might be advised to avoid troll when discussing online searches or other forms of Internet research. In that case, you are better off trawling (rather than trolling), OxfordDictionaries.com, lest your statement be confused with trolling of an entirely different sort.

Certainly this was the first time I'd seen trolling used in it's 'fishing' sense. Even though it was clear from context what was meant, it was still quite jarring.

Having read the Trolling (fishing) wikipedia page though, I now have the image in my head of a salty internet Captain shouting across a stormy forum "Set the thread to trolling speed Mr Christian".

 

[AlainDenagai]

Nostromo21[/url]":aclhpxi3]

Molehill[/url]":aclhpxi3]
Nothing in the article about this, and I don't know the distance, but on some level I'm happy to have the thing located with most of the Earth in between for when it goes off more dramatically.

Eta Car is 7500 lys from us. So, for all intents & practical purposes, we will never get anywhere near it. Unless someone actually finally invents a working wormhole generator or some form of hyper/sub-space or teleport sci-fi drive!

Current state of astrophysics makes it quite clear that we will never get to any star, even our closest Proxima Centauri, with either current, or any imaginable reaction drives (including nuclear/antimatter). The amount of fuel mass required to get anywhere in any reasonable timeframe (short of generational ships flying for millennia) is simply too long.

Ok, not generational ships, but the Breakthrough starshot and its tiny cubes travelling at 0.2c sure is intriguing as, not completely crazy.
Ok, said starshot is "only" to Alpha Centauri, not the 7,500 ly of Eta Carinae, but still, wow!

Going back to Eta Carinae, thanks for the nice article, the space/astronomy coverage on this site is excellent.
As "space porn" is concerned, this one ranks quite high indeed, maybe not as famous as the Pillars, but sooo shiny.

 

[lost]

I wonder if those one-sided eruptions from 13th and 16th century were both in same direction relative to eta Car B - which would suggest that interaction between etaCar A and B is producing those eruptions. And if both were at points when B was closest to A, it would even more strongly suggest interaction between those two as probable cause.

BTW, was accuracy of their backtracking of explosion good enough to tell within a year when it happened, or is "13th century" closest they could estimate? If it was possible to calculate within year when those one-sided explosions happened, and assuming it is possible to calculate within year orbit of A around B even at those dates (13th and 16th century), then it would be easy to answer my question above - whether A and B were in same relative position for both one-sided eruptions.

*Edit* I checked PDF of their research, and it does not look like it is possible to estimate exact years, even if given years of 1250 and 1550 are more specific than what article mentioned here. Problem seems to be high amount of guesswork about how and when ejected material was slowed down.

 

[kkeane]

Potatoswatter[/url]":1x7y7run]

kkeane[/url]":1x7y7run]We can pretty much rule out plentiful micro black holes. If they were plentiful, they would absorb most starlight, and we would not be able to see many stars.

There's no size of black hole that literally looks black and absorbs starlight. Microscopic black holes are excluded because we'd occasionally see them evaporating. Merely "small" black holes are excluded because they'd emit enough x-rays to be seen.

My favorite dark matter theory is black holes of about 30 solar masses, which would be too small for microlensing surveys and too uncommon for x-ray surveys.

Interesting. But wouldn't even such small black holes, if they really were plentiful, interfere noticeably with us viewing the stars?

Dark energy - that's another matter, though. That could be evenly distributed. But we aren't certain that it really exists; there are other possible explanations for the way the universe expands.

Dark energy is simply the energy associated with the expansion of the universe. It's contradictory to admit that the universe is expanding but to question that dark energy exists. Whatever your theory for how or why expansion is happening, that is also your theory of dark energy. At present, the Lambda-CDM model is most popular, which says that acceleration is due to a metric expansion of space. But there's no evidence for or against expansion at less than intergalactic scales, and any theory can equally seek to explain dark energy and expansion.

Well, there are other theories than dark energy, though, such as a modification of how gravity behaves on very large scales. Granted, those aren't the leading contenders.

 

[znagnetricity]

Deffinititely Quantumbuster testing site.

 

[Oak]

Korios[/url]":2x17z1k6]

Oak[/url]":2x17z1k6]
Why is that pretty likely to rule out a merger as the cause of the Great Eruption? Couldn't the merger have only happened in the 1840s (not dating literally of course, but speaking in terms of when the light reached us, as the article does), and before that, what is now η Carinae A were two death-spiralling stars?

That is, isn't something like the following possible?

Pre-1840 η Carinae A was two close stars gradually spiraling in to each other for centuries (I'll call "A1" and "A2") separated by a fraction of an AU. There could be some siphoning off of material from A2 to A1, causing asymetrical eruptions on A1.

(This siphoning would presumably be accelerated occasionally, when η Carinae B, in some of it's every-5.5-year passing within 1.6A of the pair, happened to line up, during that pass, with the line between the almost-merged pair, adding to the tidal stretching of them.)

Eventually, in the 1840s, A1 And A2 actually merged, creating a far great eruption.

(Imaginably that 5.5-year period and the 1.6 AU distance from B to the center of mass of the A1/A2 pair would vary somewhat, given the complex dynamics of a 3-body system where all 3 bodies have substantial mass relative to each other.)

(Not an expert, so anyone who knows more, feel free to poke holes.)

Because all current astrophysical models predict that if two huge stars merge they will collapse into a hypernova, and then into a quite large black hole. When two neutron stars merge they collapse into a supernova (and then into a black hole), and even when two white dwarves merge they go supernova (type Ia), with no black hole collapse. So, why didn't η Carinae collapse into a hypernova if it merged with a similarly big star?

I didn't say same size. I mentioned siphoning from one to the other, which would only happen if they were different. I was imagining something like an extremely diffuse, voluminous star (a red giant or red supergiant, no more than a few tens of solar masses but hundreds or thousand of solar radii) merging with a far more massive, but more compact, luminous blue variable star, the latter similar to what η Carinae A is now (something on the orders of about 90 solar masses and about 150 solar radii)

(Neutron stars can apparently merge with other stars without blowing them off or collapsing to a black hole, see Thorne–Żytkow object -- but that's with a red supergiant. By contrast, η Carinae A is a LBV, and I don't see mention of a LBV-neutron star hybrid being possible.)

Again though, I'm not an astrophysicist, so there could well be obvious (to an astrophysicist) reasons why what I'm suggest doesn't work at all. But since, according to the article, the notion of η Carinae A being a merger result was not otherwise considered so unlikely, but thrown into heavy doubt now only because of the extended time span of the expulsions, it seemed reasonable to wonder if some pre-merger interactions couldn't account for the earlier matter expulsions, and the merger account for the far more powerful, most recent explosion.