Talk:Eta Carinae

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"One remarkable aspect of Eta Carinae is its changing brightness. When it was first catalogued in 1677 by Edmond Halley, it was of the 4th magnitude, but later it brightened, reaching its greatest brightness in April 1843"

I don't know how to word it, but could the 2nd sentence be changed without getting too detailed, to indicate its varying brightness so readers don't think it only brightened from 1677 to 1843. Also, is it too fine a point to say "greatest *recorded* brightness in April 1843"?


  • "Sols" isn't a commonly used term among astronomers. We would be more likely to say "4 million times brighter than the Sun" or "4 million solar luminosities" or "4 million L(with a little sun symbol subscript)". Just a little nitpick. Also Eta Car is classified as a luminous blue variable, but there isn't an article for that yet. Maybe I should start it. :) - Etacar11 15:12, 20 May 2005 (UTC)

Contents

[edit] Binary star?

The article currently says:

Recent observations seem to indicate that eta Carinae is actually a binary star, the two stars orbiting each other with a period of around 5.5 years.

Says who? Do we have a reference? Let's find out who made these observations and change this to active voice. --P3d0 16:24, Jun 1, 2005 (UTC)

It's an open issue but I think most astronomers who study Eta Car are leaning towards binary. Here's some references from ADS:
--Etacar11 16:57, 1 Jun 2005 (UTC)

[edit] Eta Carina Nebula, Keyhole Nebula?

I understood the Keyhole nebula is a formation with the Eta Carina Nebula, fairly small and near the Eta Carina Star - small enough that changes in area gas and dust distribution had changed the view of the Keyhole nebula because it is illuminated by nearby stars and the shadows have moved in the view since Herschel's day.

  • You are right, the Keyhole Nebula is part of the Eta Carinae Nebula, not another name for the whole thing. It should be clarified in the article. --Etacar11 18:56, 18 August 2005 (UTC)


Clarification: The Carinae Nebula is a few degees across and includes many stars, nebulae, one of which is the Keyhole Nebula. The 'Eta Carina Nebula', i.e. ejecta thrown out of Eta Carinae and excited by same, is the Homunculus, a bipolar, or hourglass-shaped dusty nebulosity thought to originate in the 1840s and is at least 12 solar masses. Internal to the Homunculus is the Little Homunculus, an ionized hourglass-shaped nebulosity associated with the 1890's lesser event.

[edit] Typo

It said the sun has a 10 million year life span. It is billions. Corrected. :) lol Also, in reality the star is 8,000 light years away. Every where I have read about Eta says the event happened in 1841. We saw the light from the explosion in 1841. The true instance happened 8,000 years earlier. Sooooo, civilization was on the brink of coming together when this truely happened. Just thought I would point that out. I would put it into the article but I don't know how to word it properly. Since I haven't read that anywhere, I'm not sure if people would understand. It makes sense though, right? 8,000 lights years! It could be possible that the star has already blown. It could have blown 400 years after and we wouldn't know for another 200. 1841 was almost 200 years ago + 200 years into the future to equal 400 years. The intial explosion would have happened in 6041 b.c. Am I making sense?? Scientists are saying they are waiting for eta to blow like it is some kind of nearby volcano. Why the contradictions?? It could have blown in 1 a.d. and we wouldn't know, even with the most powerful telescopes, until another 6,000 years!!!! Gimme some feedback, cause' I am starting to confuse myself. If I am over looking something point it out to me pleeeease.--Guitarist6987876 23:31, 3 October 2005 (UTC)

  • It did not say the sun has a 10 million year life span. It says 10,000 million, which is equivalent to 10 billion. And a star like Eta Car has a lifetime on the order of 1 million years. --Etacar11 02:16, 4 October 2005 (UTC)

I caught that. I see the 10,000 million now. I actually didn't mean to change the 1 million year lifespan for eta. I just don't want some kid going around saying the Sun in 5 million years old because they didn't see the 10,000 part. I overlooked it, so I am sure other people will. I left the 10,000 million but I added 10 billion beside it so people who don't understand will have a clearer picture.--Guitarist6987876 02:30, 4 October 2005 (UTC)

Unfortunately, the expression billion is ambiguous, outside the US, and regions of US-influenced language. Its generally understood to be one thousand millions in the US, but some UK folk, and much of the rest of the world will understand it to be one million millions. There's a good explanation of Long and short scales and why its better to avoid using terms like billion when writing for general audiences. I'm not going to revert the edit, but I'd vote to leave it as "thousand million" and not "billion". --Raduga 17:38, 2 November 2005 (UTC)
From our frame of reference Eta Carinae erupted in the year 1841. It is perfectly right to say so.--Jyril 10:03, 4 October 2005 (UTC)

True. Technically though, false! --Guitarist6987876 14:22, 4 October 2005 (UTC)

What you mean by "technically"? If we saw Eta Carinae exploding now, the explosion occurs now even if it exploded 8000 years ago from Eta Carinae's (or from the remaining black hole's or whatever's) reference frame.--Jyril 17:57, 4 October 2005 (UTC)

So you are saying that if we could look at the light from the big bang, even though it happened 13.7 billion years ago, that the big bang is happeneing now?? It is the same concept! --Guitarist6987876 23:06, 4 October 2005 (UTC)

In a way, yes. We would see the Big Bang happening to them now. In a sense, Big Bang is an ongoing event. Some GR expert may explain better or correct me if I'm wrong.--Jyril 12:24, 14 October 2005 (UTC)
We do see the microwave background radiation, which doesn't come from the big bang itself (13.7 billion years ago) but from so close (13.7 billion - 300 000, that is 13.6997 billion years ago) that it makes little difference from our perspective. So, yes, that background is happening now, but it's also happening now everywhere else, including places billions of light years from us. Or would be if the concept of now billions of years away made any kind of common sense. Confusing, eh? --King Hildebrand 17:27, 29 August 2007 (UTC)

The Eta Carinae eruption did not occur in 6041 BC. It is not exactly 8000 light-years, but approximately 7500 to 8000 light-years. AstroHurricane001 17:31, 29 October 2006 (UTC)

[edit] Possible Eta Carinae Hypernova

I have added few lines about the possible Eta Carinae Hypernova and it's effect on Earth. I would welcome comments.

Siddiqui 21:54, 16 January 2006 (UTC)

  • What I've been given to understand (I've worked for someone who does a lot of Eta Car observation) is that we aren't in much danger in ANY case if the radiation isn't beamed in our direction (hypernovae are thought to usually be highly beamed, I think) but it could be devastating if it was... --Etacar11 22:11, 16 January 2006 (UTC)
I hope that earth is not in the direction of radiation burst. Within 24 hours whole earth will be exposed to potentially lethal radiation. The HyperNova are very unpredicatable and Eta Car may have erious implications for life on earth.
Siddiqui 17:03, 19 January 2006 (UTC)
If we go, we go. No point fretting over it.
88.110.88.75 17:15, 10 April 2006 (UTC)
Hypernova explosions are thought to travel at nearly the speed of light. Therefore, it would take about 8000 years after the explosion to reach Earth. Also, ther is a possibility that when a hypernova explodes, it just emmits a hollow sphere of radiation, with a few holes. Therefore, if it reaches Earth, it should be a wave. If you looked at Eta Carinae 8000 years after the explosion, you should see it continously brighten. It then expands into a bright ball. Soon, it explodes and the whole sky is lit up. The whole sky could reach mag. -50. Soon, the light could also emit heat and weaken the ozone layer. After the wave, some of the sun's radiation could penatrate the atmosphere and burn the sky. There could be another extinction. Note this is highly speculative and only has a 5% chance of occuring. Eta carinae probably won't explode for another 200 000 years. If it only creates a supernova, it would still reach about mag. -10, but the effects won't be as bad. Let's hope Eta Carinae holds its gas for a while. AstroHurricane001 17:43, 29 October 2006 (UTC)

[edit] This doesn't sound very NPOV

I saw an edit that an IP just made [4], and it doesn't sound very NPOV, and it has no references. Although the content sounds believable, I'm not sure where the scource came from. Also, if the content is true, someone should add references and remove the bias. This new edit seems to promote oh! look at eta carinae! it's so more important than the other stars so pay attention to it now! It made it seem like Eta Carinae jumped from 5th to 1st on the most luminous stars list. If this actually happened, someone should put it on the list. If it's not true, it should be changed so that it is true, at least according to up to date information. AstroHurricane001 22:32, 10 November 2006 (UTC)

I just made a quick edit to the star's size. Recent reports say that it has expanded. I'll post the links tonight.

[edit] Table

The table takes up the entire page. I'm not sure how to fix it, otherwise I would. Darry2385 02:50, 30 April 2007 (UTC)

[edit] Apparent magnitude out of date?

There are two conflicting magnitudes listed in the article. It appears eta car has apparent magnitude around 5.1: AAVSO

Someone should mention that this explosion is mostly harmless because main burst will not hit Earth. Even by 7500 ly we would be toasted in direct hit. Source: [here] .

"Note that the lobes appear to be tilted away from us by about 40 degrees or so. That’s a good thing. When stars like Eta Carinae explode, they tend to shoot of beams of energy and matter that, at its distance of 7500 light years, could kill every living thing on Earth. But since it’s pointed away from us, all we’ll get is a spectacular light show."

[edit] How close to supernova?

This recent article claims that Eta Carinae will almost certainly go supernova in the next few centuries, whereas the article suggests it may be up to 1 million years from now. Which is more accurate? MOXFYRE (contrib) 15:30, 23 June 2007 (UTC)

[edit] proposed move/redirect

Hi. For some reason, this article keeps calling the star Eta Carinæ. So, I am suggesting a move to (or redirect from) this page. Please settle on a consensus, and indicate support or oppose suggestion below. Please include a reason, and a suggestion on what to do. Thanks. ~AH1(TCU) 18:53, 29 June 2007 (UTC)

  • I think that that should be a redirect, since no one is going to type that in on a keyboard. Leave the article itself where it is. My two cents. --Etacar11 19:26, 29 June 2007 (UTC)
There... I made the redirect Eta Carinæ. Use of the æ ligature in English is pretty inconsistent, so it probably makes sense to have a redirect. MOXFYRE (contrib) 19:52, 29 June 2007 (UTC)
I suggest either a move to the correct name, or the use of {{wrongtitle}}. Though there aren't actually any technical restrictions preventing us using the correct name... Modest Genius talk 15:12, 4 July 2007 (UTC)
I also suggest we merge Homunculus Nebula into this, I've slapped merge tags on them both Modest Genius talk 15:23, 4 July 2007 (UTC)
Why? They are different things. --IanOsgood 19:13, 12 July 2007 (UTC)
I agree, they should not be merged. Merging doesn't seem appropriate here... the two articles cover different, but related astronomical bodies. They don't duplicate each other significantly, and the distinction between the topics is clear-cut. MOXFYRE (contrib) 13:47, 13 July 2007 (UTC)
Hmmm, perhaps it's clear to some, but Joe Public coming along and glancing at the articles will just see the same picture, and will get horribly confused; this is especially true if he reads the articles properly and finds two different things described. besides, it's rather difficult to have any understanding of the nebula without an understanding of the central star(s). It's not like putting it all on one page would be unnecessarily long or misleading - they're inextricably related. Would you advocate separate articles for HD 44179 and the Red Rectangle? The distinction is virtually identical to that between Eta Car and the Homonculus. Modest Genius talk 21:16, 18 July 2007 (UTC)
Acting as 'Joe Public'. Arrived here via today's Picture of the Day on the Main Page and via the Homonculus. Seeing Homonculus twice in succession seemed initially a bit naff. Would a label such as 'Eta Carina within the Homunculus Nebula' help? Vote to keep articles separate - other star images displayed within a nebula from a separate article Pistol Star. --Eddie | Talk 07:24, 20 August 2007 (UTC)

The word should be written "Carinae". The "æ" is a typographical ligature, not a feature of the spelling (which has two letters; it's an ordinary Latin 1st declension genitive). See æ for details, noting "Both classical and present practice is to write the letters separately". I've corrected the typography in the article. Gdr 14:04, 5 July 2007 (UTC)

fair enough Modest Genius talk 22:05, 10 July 2007 (UTC)

[edit] I Disagree

I Disagree beteween the merge becuase the articles are about different hypernovas it isnt a hypernova page where you can just chunk in some information if we merge it how can people tell beteween Eta Carinae and Homunculus Nebula. Ratesreal1 | Talk 08:16, 20 November 2007 (ETC)

[edit] Argument

Uh, what? Eta Carinae is a star, and the Homonculus Nebula is a nebula around the star, caused by the star. Neither are hypernovae (which is an event not an object anyway), and people could tell the difference by the difference being explained in the article. The point I was trying to make was that it is impossible to explain the Homonculus without knowledge of the star, and thus they should be explained together, rather than in two places. Modest Genius talk 22:12, 21 November 2007 (UTC)