Talk:Supernova

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Featured article Supernova is a featured article; it (or a previous version of it) has been identified as one of the best articles produced by the Wikipedia community. Even so, if you can update or improve it, please do so.
Good topic star Supernova is the main article in the Classes of supernovae series, a good topic. This is identified as among the best series of articles produced by the Wikipedia community. If you can update or improve it, please do so.
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Pronunciation[edit]

As far as I've seen, there is no WP standard that says an article must insert a flow-disrupting pronunciation guide in the first sentence of an article. Hence I moved it down following the definition and turned it into a more complete sentence. If there is a concern with this change, please clarify. Thank you.—RJH (talk) 19:22, 2 May 2011 (UTC)

I've erased "pron" from the first formula so that it'd look more text-like. All the options preserved. Josh, linguist (talk) 11:39, 19 March 2013 (UTC)

New candidate supernova class[edit]

See:

Regards, RJH (talk) 17:24, 8 June 2011 (UTC)

Close supernova[edit]

I just read about a supernova that is supposed to happen very soon, that is extremely close to earth. A more proficient editor than me should add it. Here's the article. http://science.cabot.ac.uk/index.php/2011/10/a-star-set-to-blow/

75.92.160.60 (talk) 21:27, 2 October 2011 (UTC)

It would be more appropriate for History of supernova observation. This is an article about supernovae in general. Regards, RJH (talk) 19:20, 4 October 2011 (UTC)

Newer Supernova Than stated in this article has now been confirmed.[edit]

G1.9+0.3 Has been confirmed as the youngest supernova within the Milky Way galaxy. ref. http://news.nationalgeographic.com/news/2008/05/080514-supernova_2.html

To summarize:

Supernova G1.9+0.3 discovered by Stephen Reynolds and his team at North Carolina State University has been confirmed as the youngest supernova discovered to date, it is estimated at only 140 years old and located within the constellation of Sagittarius. Although obscured by interstellar mass at the time of it's explosion recent studies of it have shown it to be a rapidly expanding and very young supernova, currently the youngest confirmed by astronomers. — Preceding unsigned comment added by 184.59.144.219 (talk) 04:09, 11 February 2012 (UTC)

Date of the word supernova[edit]

The introduction says that "supernova" was first used in print in 1926 (according to Merriam-Webster). Under "Discovery" it says that it was first used in a lecture in 1931 and at a meeting of the APS in 1933. In the article about Fritz Zwicky it says that the word was coined by him and Walter Baade in 1934.

In Fritz Zwicky: Novae Become Supernovae by T Koenig (http://articles.adsabs.harvard.edu//full/2005ASPC..342...53K/0000058.000.html) it says that Zwicky and Baade had been using the term since 1931 and that the first publication in print was by Knut Lundmark in 1933 (article dated Dec 31 1932).

Zwicky writes himself in Types of novae (http://authors.library.caltech.edu/4785/1/ZWIrmp40.pdf footnote on page 85): Baade and I first introduced the term "supernovae" in seminars and in a lecture course on astrophysics at the California Institute of Technology in 1931.

This source seems to sum it up pretty well:
Osterbrock, D. E. (December 2001), "Who Really Coined the Word Supernova? Who First Predicted Neutron Stars?", Bulletin of the American Astronomical Society 33: 1330, Bibcode:2001AAS...199.1501O 
Regards, RJH (talk) 22:51, 25 February 2012 (UTC)
But "The word supernova was coined by Swiss astrophysicist and astronomer Fritz Zwicky, and was first used in print in 1926", as it says in the introduction, is contradictory to that it was first used by Zwicky in 1931 and also to that it was first used in print in 1933. And 1934 as given in in the article on Fritz Zwicky is also contradictory. — Preceding unsigned comment added by 83.254.200.12 (talk) 09:01, 26 February 2012 (UTC)
Yes, I agree. The introduction, and its corresponding source, would appear to be in error. We should use the Osterbrock (2001) source for consistency. Regards, RJH (talk) 20:19, 28 February 2012 (UTC)

About the overall structure of the article wrt to my recently reverted mass edit[edit]

I did a bigger than usual, though content retaining, edit to the article the other day, which was promptly undone. Though I might have been somewhat hasty instead of simply bold, I'd like to raise two points which I think should be corrected within the article.

First, the introductory chapter contains lots of stuff that simply isn't relevant to someone trying to find out what a supernova is, at the surface level. True, what I tried to do with my edits was to shorten it, because I have a problem with overly long intros. And I know that brevity is formally very much not a criterion for the intro, as a matter of written policy.

But still, relevance to a first time learner I believe is. From that viewpoint I would think what has to be told is a) it's an unusually and suddenly luminous star, b) long after we saw them the first time, we learned that there are many different kinds of them, c) one or two representative examples of the thing, and d) the fact that they are believed to be caused by different modes of runaway fusion. That's it; I believe the rest of the details should be pushed down into the body of the article, because before you can understand the differences, you need a huge lot of preliminary text to understand it, which can only fit the body format.

The lead is written according to the guidelines in WP:LEAD in that it is intended as a summary of the primary points of the article. It is three paragraphs long, which is less than the maximum for a long article like this. I found your edits to the lead to be heavy handed and overly extensive. It has been thoroughly reviewed by many editors (hence the FA rating), and thus I believe it is just fine for the purposes of this encyclopedia. Please keep in mind that your concern about the supposed excess length is one opinion among many; other reviewers find brief leads to be equally objectionable. I'd like to keep it in balance with the prevailing standards and past consensus. Regards, RJH (talk) 18:25, 20 June 2012 (UTC)
That is then why I brought my concerns onto the talk page. I'm arguing for a particular stylistic choice, which we evidently do not agree about. Both those choices fall within the guidelines and you've already reverted my idea. Thus, I'm seeking further output and consensus before touching the article further. Decoy (talk) 22:59, 20 June 2012 (UTC)

The second part is that, right now, the physical theory concerning supernovas is interspersed widely within the article, as is the astronomical data we have of them. Your mileage may vary, but I think those aspects should be separated and concentrated into their own sections, so as to make for tighter presentation, which can then also be more easily found from the topmost content listing. Especially since I think people simply interested in the night sky and the ones interested in stellar dynamics are two different crowds, with two different needs. As such, I'd advocate a wholesale content-retaining reorganization at the level of single claims. That is not as big or difficult as it sounds, but it might seriously help a total newcomer internalize the contents better, while not taking away anything from the expert.

The physical models for supernova are contained in the "Current models" section, so I find your statement puzzling. Note that the lead should be redundant with elements of the article body, which is why we don't need to relocate content from the lead into the article. To me the article flow is logical and I'll object to a wholesale rewrite without a solid plan and a wider consensus. Perhaps you could clarify your perspective with some specific examples? Regards, RJH (talk) 18:30, 20 June 2012 (UTC)
I mostly agree. But I think the redundancy in the introductory section should be minimal, and that it should only mention, not explain or reason with, what is contained in the body. I agree that my edit was heavy handed, and I'm happy that you reverted it. But I also believe something even better could be found between the basic idea of what is now in there and what I tried to put there.
Two particular examples wrt the intro chapter would be the precise velocity estimate of what supernovas put out, and the mention of shockwaves in the interstellar medium. They are sequelae of the process, not defining factors of what a supernova really is. In fact, they vary widely depending on what the local matter density actually is and how the supernova happens to come into being. What is left of it as well; all of that is, I think, better handled in the body of the article, by moving the relevant content there. Decoy (talk) 22:59, 20 June 2012 (UTC)

Finally, don't get me wrong. The article is exceptionally good as it stands, as evidenced by its featured status. It's just that I think it could be even better. Right now I'd say its structure is at the level of a rather good encyclopedia article. But it ain't yet a Feynmann lecture, where every question is answered precisely when you were about to ask it in the logical procession of things, if you know what I mean. Decoy (talk) 18:06, 20 June 2012 (UTC)

This is an encyclopedic article, so it should most definitely not be turned into a Feynmann lecture. (Yes I have read Feynmann.) If you want to build an in depth presentation, I strongly urge you to try the Wikiversity or Wikibooks projects; those have very different goals than a straight-forward encyclopedic presentation of the facts. Regards, RJH (talk) 18:30, 20 June 2012 (UTC)
I agree that the summary paragraph needs work. It can't be a coincidence that this reverted edit was almost identical to one I tried to make a few weeks back. The summary may only be three paragraphs, but one of those paragraphs (the only one that really has a problem) is overly long and not at all a concise summary of any portion of the rest of the article. Some of it is simply incorrect. My response to these problems was just to remove three quarters of that paragraph, but perhaps it could be written in a better way. Lithopsian (talk) 20:10, 20 June 2012 (UTC)
The concern I had with Lithopsian's modification to the lead is that it just moved a chunk of text down into the article; that should not be happening because the lead should be a summary of the article. It sounds like we need to start by reaching a consensus on how to write the lead. The consensus rule of thumb on the lead is to have at least one sentence per article section, and to mention the major points in the presentation.
As it happens, the large paragraph in question was previously two separate paragraphs; somebody came along and combined them. (Compare, for example, to the version at the FA promotion.) This sort of trivial modification happens frequently on Wikipedia and it isn't always beneficial. It should be easy enough to split it again. However, I can guarantee you that whatever we come up with will not remain intact over time. All we can do is try to maintain it in a somewhat recognizable form. Regards, RJH (talk) 21:16, 20 June 2012 (UTC)
What I mean by my reference to the Feynman Lectures is not about their content, but their explanatory style and well-structured flow of thought. They go to extraordinary lengths in teaching stuff in an order that is understandable, easily memorable, and logic-wise coherent. I believe such a style of presentation is a merit to an encyclopedia article as well, even if it's patently clear that these two genres are very separate an sich.
So, I mostly agree. But I wouldn't call reorganization which leaves the content intact, while aiming to improve its flow at the same time, trivial. Nor would I stop text movement which aims to achieve those goals. I did my changes precisely because I care about that sort of stuff quite a lot. I don't dispute your viewpoint about my heavy-handedness or the one about my lack of proper grammar, since I'm not a native speaker of English myself. But at the same time, I do think I have a point to make about the flow of thought. Perhaps *especially* because I'm what they call an "avid amateur", so that I can look at the article from a learner's point of view. Decoy (talk) 22:59, 20 June 2012 (UTC)
I've edited that second paragraph in the summary. I've removed or reword things that are inaccurate. It is considerably shorter but at least not misleading now. I think it is a good length and says what needs to be said? Lithopsian (talk) 22:47, 21 June 2012 (UTC)
I'm basically done with the structural changes and edits, mostly to the sections on classification and models. These should now be consistent with current research. I'm still waiting on feedback about merging the type II and type Ib/c articles into a single core collapse article, and possibly much of the core collapse section could then go there, leaving just a summary in this article because it is quite long right now with a lot of detail. Lithopsian (talk) 17:58, 24 June 2012 (UTC)

Neon over oxygen?[edit]

In the diagram http://en.wikipedia.org/wiki/File:Evolved_star_fusion_shells.svg, it shows the shell of neon (atomic number 10) above oxygen (atomic number 8). It this correct? http://en.wikipedia.org/wiki/White_dwarf#Stars_with_low_to_medium_mass states that "If the mass of a main-sequence star is between approximately 0.5 and 8 solar masses, its core will become sufficiently hot to fuse helium into carbon and oxygen via the triple-alpha process, but it will never become sufficiently hot to fuse carbon into neon." So in this star, why would Neon-20 float above Oxygen-16?

As I am not an astrophysicist and lack the skills to modify that diagram anyway, I thought I would start this discussion. If I am wrong, it would be nice if this good article explained why the neon shell would be above the oxygen. 71.22.115.39 (talk) 16:15, 25 November 2012 (UTC)OxyB4Neon

The image is hopelessly naive and over-simplified. Still, for what its worth, Neon starts burning at a lower temperature, and therefore before, Oxygen, and any Neon shell will be found below the Carbon shell and above the Oxygen shells. So the image should be considered correct. Lithopsian (talk) 18:13, 25 November 2012 (UTC)

So, I guess the triple-alpha process only produces some oxygen and is overshadowed by a later process after neon burning. Okay, then why would the oxygen not bubble above the neon, given it's lighter atomic weight?

Also, looking at http://en.wikipedia.org/wiki/Alpha_process, it shows that you cannot get neon with oxygen as a precursor. What am I missing? oh. I found it, at http://en.wikipedia.org/wiki/Carbon-burning_process. It seems that carbon-burning results in sodium, magnesium, oxygen as well as neon. Still, this only occurs in stars great then 8 solar mass so I am at a loss as to why the oxygen does not float above the neon.71.22.115.39 (talk) 20:37, 2 December 2012 (UTC) OxyB4Neon

Nothing to do with "floating". This is burning. Neon burns first. The diagram indicates the location of shell burning, not the location of actual elements. Various elements occur mixed all over the place, especially Magnesium, Oxygen, and Neon which are all produced together from Carbon. Lithopsian (talk) 20:43, 2 December 2012 (UTC)

Classification[edit]

Should this be mentioned?

Types of Supernovae

Type Ia. These result from some binary star systems... Type II. These supernovae occur at the end of a massive star's lifetime...


However, these types of supernovae were originally classified based on the existence of hydrogen spectral lines: Type Ia spectra do not show hydrogen lines, while Type II spectra do.

... However, if the original star was so massive that its strong stellar wind had already blown off the hydrogen from its atmosphere by the time of the explosion, then it too will not show hydrogen spectral lines. These supernovae are often called Type Ib supernovae, despite really being part of the Type II class of supernovae. Looking at this discrepancy between our modern classification, which is based on a true difference in how supernovae explode, and the historical classification, which is based on early observations, one can see how classifications in science can change over time as we better understand the natural world.

(Those were quotations.) Josh, linguist (talk) 12:01, 19 March 2013 (UTC)

It is mentioned, in great detail. Possibly too much detail. Read the sections on supernova models. It could be more succinct in this top level article, which might be easier to follow, but until the detail articles are rationalised I don't want to delegate all the detail. Lithopsian (talk) 12:39, 19 March 2013 (UTC)
First, I think it still should be mentioned somehow in the "lede" of the pertaining section. That the "taxonomy" doesn't represent primary differences in general.
Second. You say the article should be liter or what? Then I suggest if we draw not that (or another) formal classification first, but give a trivial "taxonomy" on the matter — types (or 'kinds') of supernovae - depending on the processes involved. THEN it's followed by the table with that formal classification. What do you think?
AN IDEA! What about preceding the "Classification" section by that new one to depict those major types of blow-ups I meant? For example, we could depict the few different known types of environment producing SNe. If that is described in the following "Current models" section, I mean, for an amateur reader (especially when s/he goes into this for the first time or so), some rough phenomenon adumbration may come first. You may say the overall idea might already be gained in the article's lede, but I think, if the lede is delivering the "main overall" — i.e. what t.f. it is (the matter leaps out due to the pressure of either sort), the suggested "distinguishing" section could roughly describe the needed circumstances in the least formal way. Or, either way, we could shift the existent sections — with making some ordering corrections.
PS. As for that "detailedness" of this article you mentioned above, I saw some score of rather much more "abundant-in" ones, now in comparison, this one looks not at all very monstrous for me:) Josh, linguist (talk) 15:04, 21 March 2013 (UTC)
The lead does mention the two types, but I feel it is rather lost in the second paragraph. Have to be careful messing with the lead on a featured article but it could probably be improved. Lithopsian (talk) 22:26, 21 March 2013 (UTC)

New Type of Supernova[edit]

I think this should be also mentiond: Harvard press release: new kind of supernova. But my english is not so good. Can someone ad this? Catadupa (talk) 09:24, 27 March 2013 (UTC)

It doesn't seem major.  ? Josh, linguist (talk) 13:09, 27 March 2013 (UTC)
It isn't major, but it still deserves a mention. Probably in the type Ia detail article. I thought it might already be there, but a quick look doesn't show anything. If nothing else, it is interesting because it blurs the line between the non-destructive novae and supernovae which completely destroy the star. Lithopsian (talk) 13:51, 27 March 2013 (UTC)

Here are articles I found about it:

  • Foley,, Ryan J.; P. J. Challis, R. Chornock, M. Ganeshalingam, W. Li, G. H. Marion, N. I. Morrell, G. Pignata, M. D. Stritzinger, J. M. Silverman, X. Wang, J. P. Anderson, A. V. Filippenko, W. L. Freedman, M. Hamuy, S. W. Jha, R. P. Kirshner, C. McCully, S. E. Persson, M. M. Phillips, D. E. Reichart, A. M. Soderberg (10 Dec 2012). "Type Iax Supernovae: A New Class of Stellar Explosion". arXiv preprint arXiv:1212.2209v2. Retrieved 28 March 2013. 
  • Wang, Bo; Stephen Justham, Zhanwen Han (6 Jan 2013). "Double-detonation explosions as progenitors of type Iax supernovae". arXiv preprint arXiv:1301.1047. Retrieved 28 March 2013. 

I hope they help. --Richard-of-Earth (talk) 19:14, 28 March 2013 (UTC)

They look same...
To pile it out, Astronomers have discovered a new miniature version of a supernova. Josh, linguist (talk) 12:41, 2 April 2013 (UTC)
The links above are wrong, but there really are two papers. They are both referenced in the article already. We should avoid using press releases and other web pages as references when the real deal is available. Lithopsian (talk) 14:57, 2 April 2013 (UTC)

Nomenclature[edit]

Article should clarify whether the "SN[YEAR] XX" naming system would apply to Milky Way objects - I don't think that it does. Presumably we would have (for example) "Supernova Sagittarii 2013", with GCVS name assigned shortly thereafter (e.g. "V5991 Sagittarii"), as opposed to (e.g.) "SN 2013mb", if a Milky Way supernova were discovered in modern times. — Preceding unsigned comment added by 184.47.125.210 (talk) 19:00, 22 August 2013 (UTC)

Asymmetry section[edit]

I do not understand the first sentence in that section and I think that probably a word is missing.--Jrm2007 (talk) 23:45, 1 November 2013 (UTC)

4 diagrams (could be useful)[edit]

(with google translator help) Hallo, I did this job for Italian Graphic Lab, I've also prepared an english version of them, if somebody wants to take a look at them... in the future they could become useful somewere. File:Supernovae as initial mass-metallicity.svg File:Remnants of single massive stars.svg File:Collapsar as initial mass-metallicity.svg File:Jet supernovae as initial mass-metallicity.svg -- Fulvio 314 10:52, 28 November 2013 (UTC)