Talk:Eta Carinae

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Variability[edit]

"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"? — Preceding unsigned comment added by Jeandré du Toit (talkcontribs) 11:16, 19 January 2003

Apparent magnitude out of date?[edit]

There are two conflicting magnitudes listed in the article. It appears eta car has apparent magnitude around 5.1: AAVSO — Preceding unsigned comment added by 132.206.150.195 (talkcontribs) 08:48, 30 May 2007

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." — Preceding unsigned comment added by 80.51.70.116 (talkcontribs) 13:19, 21 June 2007

New Mass Model for Eta Carinae[edit]

According to the source given for the mass values of the system, [1], it states that their preferred model of the system has the mass value of Eta Carinae A at 200 M and Eta Carinae B at 80 M. They state in the article, and I quote, "We therefore conclude that in order to get a good fit for the GE, mass transfer must be taken into account, and that the two stars of η Car are much more massive than usually thought." But not only this. The article also states, "We used two models. Model "MTz" assumes (wrongly) that the secondary is not evolved, and we took it to be a ZAMS star." This proves that the mass value of 170 M for the primary star is incorrect. The article also states,"We conclude that it is not possible, under our assumptions, to use a low-mass system of ~150 M to fit the rises in the light curve of the GE. This proves that according to their measurements, that the common model for the system is not massive enough to have caused as significant a change in the magnitude of the system during the Great Eruption. I would greatly appreciate if this information could be included in the article and the List of most massive stars article. I also appreciate the feedback from Lithopsian and Tarlneustaedter. Thanks.

Comment By:174.110.102.238- 00:35, 19 March 2016 (UTC).

Glancing through the article, it appears to be an interesting analysis, but (from my perspective), far from definitive. The article derives different masses than other approaches have, but that does not invalidate the other approaches - it simply accentuates the uncertainty. At this point, I'd suggest that the range 120-200 is probably still appropriate. I would not even put 200 as the most likely value. Regards, Tarl.Neustaedter (talk)
I agree. It is highly speculative at this point, and basically not confirmed by any other research. Of course much about Eta Carinae is highly speculative, but when broadly the same model is supported by a range of researchers then we can state it as (for now) "fact". Even the Kashi-Soker papers refer to it as the Standard Model. At the very least, we should present the standard model as having an equal weighting to the new model. Given that a range of more recent papers essentially gloss over the Kashi-Soker models and keep quoting the standard model, I think it would be quite justifiable to drop the high mass values from the starbox altogether and just mention them in the text. They might be the "preferred" model of one research team, but certainly not of the wider astronomical research community. Lithopsian (talk) 15:29, 20 March 2016 (UTC)
Oh, and I moved this article to the end of the talk page so it could be found. When talk page comments are added, it's customary to create new sections at the bottom of the page - see the "new section" link at the top of the talk page. Regards, Tarl.Neustaedter (talk) 01:32, 19 March 2016 (UTC)

References

  1. ^ Kashi, A.; Soker, N. (2010). "Periastron Passage Triggering of the 19th Century Eruptions of Eta Carinae". The Astrophysical Journal. 723: 602. arXiv:0912.1439Freely accessible. Bibcode:2010ApJ...723..602K. doi:10.1088/0004-637X/723/1/602. 

Time to describe the mechanism of the Great Eruption?[edit]

The article currently describes observations of the Great Eruption, but says little to nothing about what caused it. If I remember rightly, this was done simply because we don't know what caused it, but there are now at least three models and it may be worth describing them. The "classic" model is simply a super-Eddington wind which is effectively a larger version of more normal LBV instabilities. This has looked progressively less and less likely as the scale of the eruption has been determined. The mass transfer model is basically the release of gravitational potential energy from primary wind material accreted onto the secondary, triggered by a combination of LBV-type expansion of the primary and orbital interaction with the secondary. Another model is the "explosive" model where a sub-supernova scale explosive event ejects a substantial fraction of the star, with the high luminosity caused by conversion of the kinetic energy to radiation in the same way as type IIn supernova, basically colliding with previously ejected circumstellar material. Yes? No? Did I miss anything? Lithopsian (talk) 17:48, 20 March 2016 (UTC)

@Lithopsian: I think some note would be good to add. Cas Liber (talk · contribs) 21:17, 4 September 2016 (UTC)

New high-res images of the star's disk[edit]

http://www.space.com/34445-eta-carinae-explosive-star-system-best-views.html

--101.161.174.247 (talk) 07:35, 21 October 2016 (UTC)