Talk:Planetary nebula - Misplaced Pages

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Planetary nebula is a former featured article. Please see the links under Article milestones below for its original nomination page (for older articles, check the nomination archive) and why it was removed.

This article appeared on Misplaced Pages's Main Page as Today's featured article on December 31, 2004.

Article milestones
Date	Process	Result
December 16, 2004	Featured article candidate	Promoted
November 25, 2009	Featured article review	Kept
December 16, 2014	Featured article review	Demoted

Current status: Former featured article

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Typical stellar lifetime

The article states that a typical stellar lifetime is "several billion years" howeve the article on Red Dwarfs states that "Red dwarfs are the most common star type in the Galaxy" and also shows that their lifetimes are measured in trillions and not billions of years. I suggest that the article be changed to state that a typical stellar lifetimes is in excess of more than a trillion years or be changed to use our own sun's main sequence lifetime as a reference, which will be about 9 or 10 billion years.

76.169.69.254 (talk) 01:46, 15 October 2009 (UTC)

Image

I worked on the project that produced this image (one of the et al. in Chu et al.) and the image processing was done at NASA. I believe, therefore, it's in the public domain and I have the right to give permission for its GDL release. Please contact me if there's a problem with either assumption! -- April

If the work is in the public domain, I have just as much right as you do to release it under a licence, ie none. Sorry. Taxpayers paid for Hubble, therefore we own any images coming out of it. -AC

I have a PhD in the abundances of heavy elements in planetary nebulae, so couldn't resist writing a bit on this page. Apologies to all if I've got too technical! Please edit ruthlessly if I have. (Worldtraveller)

"In other galaxies, planetary nebulae may be the only objects observable enough to yield useful abundance information." Apologies for removing the "abundance" part, I misunderstood it and thought of it as either bad grammar or a forgotten piece of an older sentence. -F. Delpierre

No probs - it made me realise that section could be a bit clearer so I've tweaked it a bit more. Hope that makes it clearer. Worldtraveller 01:35, 31 Dec 2004 (UTC)

Images from this article are in wikimedia commons now. --213.194.213.59 04:10, 1 Jan 2005 (UTC)

Plasma/Gas

I just changed 'plasma' to 'gas' in the intro., because although the majority of a planetary nebula will be plasma, there are often neutral species present so the more general description is better, I think. Worldtraveller 23:49, 2 Jan 2005 (UTC)

Slashdot News

This story was linked by Slashdot on Jan 5 2005. Coincidentally, the slashdot heading linked to this article as a reference on planetary nebula(e for plural?). Anyway, apparently the article contains some new findings apropos to the mystery of magnetic fields and why the nebulae aren't usually round. Unfortunately it's 3 in the morning here (too late to write articles by my clock) and I know nothing about the subject. I thought you all should know though.Matthewcieplak 21:20, 6 Jan 2005 (UTC)

This news had been added to the intro, with a statement that 'it is likely that magnetic fields are responsible' for diverse shapes of planetary nebulae. I thought that sounded a bit strong - this is just one paper, with 2/5 definite detections of magnetic fields and 2/5 probable detections. It's still just one of many competing theories, so I've removed the sentence from the intro and added a bit to the 'open questions' section. Worldtraveller 20:22, 23 Jan 2005 (UTC)

Recombination

In the lifetime section of the article, recombination is linked to a disambiguation page which doesn't seem to have anything to do with planetary nebulae. I don't know how to fix this right off the top of my head, which is why I'm mentioning it on this talk page. --Arkuat 09:14, 11 March 2006 (UTC)

Thanks for pointing that out - I've made it link to a more appropriate article. Worldtraveller 16:01, 11 March 2006 (UTC)

Ah, that makes much more sense now. Thanks for the fix. --Arkuat 07:35, 12 March 2006 (UTC)

Characteristics

Forgive me if i'm just being naive, but:

"with a density generally around 1000 particles per cm³ - which is about a million billion billion times less dense than the earth's atmosphere"

What is a million billion billion? That really does not seem like a real number to me. Is this an editing error where extra words were not deleted?

1,000,000,000,000,000,000,000,000 ?

Juniorrachel 20:11, 20 March 2006 (UTC)

Don't think there was an error, no! The figure you've written out is a million billion billion, and planetary nebulae really are a million billion billion times less dense than the earth's atmosphere. We could say 10 times less dense, or write out the number, but I think using the commonly known words is probably the best way of communicating what is intended. Worldtraveller 18:40, 23 March 2006 (UTC)

Thanks for clearing that up. :) Juniorrachel 13:43, 4 April 2006 (UTC)

Actually, Juniorrachel had a point. The Earth's atmosphere has a mean molar mass of 29 g/mol, so 10 particles/cm would imply a density of 48 kg/cm—clearly ridiculous. In fact, air contains just 2.5×10 molecules/cm. Dumbing this down, as seems to be required, makes a 1000 particles/cm planetary nebula just 25 million billion times less dense than this stuff we breathe.
—Herbee 00:12, 22 January 2007 (UTC)

Do you have a reference for these figures? —The preceding unsigned comment was added by 81.179.64.173 (talk) 08:50, 23 January 2007 (UTC).

Stingray nebula

the article Stingray Nebula is on the list of orphan articles because nothing links to it. It is certainly not up to the standards of other planetary nebulae articles and should also be listed in various lists and tables. Will someone adopt this article? Thatcher131 20:54, 24 May 2006 (UTC)

This article has been un-orphaned and expanded with citations. WilliamKF 01:08, 14 February 2007 (UTC)

Version 0.5

This article has been selected for release into Version 0.5 due to its importance and quality; however, is it possible to get the sparse bare links in the article converted to references? Also, the article uses footnotes, so it could benefit from the cite.php citation system. Tito xd 23:20, 31 May 2006 (UTC)

Hadn't noticed this post earlier - sorry about that. I've converted the refs to the cite.php format now. Worldtraveller 11:25, 12 June 2006 (UTC)

Affection on Earth?

Could planetary nebulas affect Earth like the supernova explotions or the Gamma-Ray Busts?--Spaceman 16:26, 10 July 2006 (UTC)

Err... gamma-ray busts? :-) I would think probably not, unless you mean a planetary nebula generated by an evolved Sun. — RJH (talk) 17:14, 11 January 2007 (UTC)

Wings of a Butterfly Nebula

Needs a home. I'm currently working on orphaned articles. Any suggestions? meatclerk 10:07, 13 September 2006 (UTC)

Links needed

AGB giants produce planetaries, as far as I believe I know. Thus some link from here to Asymptotic Giant Branch? Rursus 22:39, 8 January 2007 (UTC)

A link is in the See also section. WilliamKF 01:07, 14 February 2007 (UTC)

Thermal pulses from double-shell?

It was pointed out to me elsewhere that the thermal pulses may be produced due to instability of a double-shell (H-He) burning phase (during the post-AGB evolution of a <8 solar mass star). I'm not sure that the text quite captures this detail. — RJH (talk) 17:33, 8 June 2007 (UTC)

Updated the information on the PNe numbers in the Galaxy

I have taken the liberty of updating the information on the PNe page due to the significant new Galactic PNe that have been reported in the literature and have also updated the references. I also included a reference to the recent high quality H-alpha survey which permitted these discoveries. Out of interest I attach the web link to this powerful on-line survey: http://www-wfau.roe.ac.uk/sss/halpha/ as the entire survey is available in digital form for dowload as fits images. Respectfully yours Quentin A Parker 31/07/07130.79.129.227 09:06, 29 July 2007 (UTC)

1500 vs 3000?

The intro says there are 1500 nebula, while "Numbers and distribution" says 3000. Beast of traal T C _ 03:26, 3 March 2008 (UTC)Beast of traal

30000K

The article says that: "When the exposed surface reaches a temperature of about 30,000K, there are enough ultraviolet photons being emitted to ionize the ejected atmosphere, making it glow. The cloud has then become a planetary nebula." But the rest of the article mentions temperatures as high as 100 million K. Is that 30,000K right? Because it would seem logical that the exposed surface of the star is VERY hot. Am I wrong? 195.50.206.252 (talk) 11:14, 26 April 2008 (UTC)

Yet to be discovered!?

The section Numbers and distribution says

However, there has yet to be an established case of a planetary nebula discovered in an open cluster.

Now, why should there be any at all? If open clusters are dispersed after say 400 My (Open_cluster#Eventual_fate), then any open cluster planetary nebula would be very rare indeed, and only in clusters which is sizeable enough to be a border case to a globular cluster. Supernovae would be more likely, but if that happens the cluster might be disrupted by those supernovae. Said: Rursus ☻ 10:07, 22 June 2008 (UTC)

Wish: PNCS

Central star that is. Some more needed on them. I -ed to the article Blue dwarf but did not find PNCS there, despite Blue Dwarf might refer to PNCS:es, although the term may be obsolete. Said: Rursus (☻) 09:20, 17 September 2008 (UTC)

Not obsolete. When googling on "blue dwarf star" (including dbl blipps), I found 70% references to Blueish (B) main sequence stars, and the rest to real blue dwarfs, mostly the Ring Neb CS. Said: Rursus (☻) 09:38, 17 September 2008 (UTC)

{{Editsemiprotected}} request

{{editsemiprotected}}The word "nebulae" seems to be missing from the last sentence of the first paragraph in the Characteristics section. Pseudothink (talk) 23:53, 4 December 2009 (UTC)

Done. Thank you for your contribution to Misplaced Pages. In the future, though, please place requests at the bottom of a page, unless they are related to an earlier discussion; this facilitates finding your request. Intelligentsium 00:02, 5 December 2009 (UTC)

Super Planetary Nebulae

Super Planetary Nebula is a new objet discovered. Not sure how to add it into the article.

http://www.physorg.com/news169477900.html

Fullerenes discovered in a planetary nebula

Buckminsterfullerenes were recently observed in a planetary nebula by spectroscopy. Perhaps someone can add this to the article. link to Astronomy article

Video

Isn't the video currently on the page a Type 1a supernova? I see what looks like a pulsar or other dense stellar remnant attracting most of the star's mass, which then causes the supernova. Am I mistaken? DingoTech (talk) 02:50, 26 June 2011 (UTC)DingoTech

Actually, I think that video is of Eta Carinae. At any rate, it does NOT show a classic planetary nebula. :) (Stephen Poole) — Preceding unsigned comment added by 216.180.114.40 (talk) 13:12, 1 April 2013 (UTC)

Jet

though we have an animation for Flemming 1, there's no text explaining the creation of symmetric jets. Perhaps this would make a good resource -- 70.24.186.245 (talk) 14:29, 10 November 2012 (UTC)

Preferred name: Stellar Remnant Nebula

Stellar remnant nebula is the preferred name because

it describes the origins of the nebula more accurately
the name parallels that of supernova remnant nebula
one doesn't have to immediately explain that it has nothing to do with planets. — Preceding unsigned comment added by Lehasa (talk • contribs) 15:04, 6 January 2013 (UTC)

Yeah, nice idea but until you've persuaded astronomers to adopt your "preferred name", the name actually used is what we are stuck with. — Preceding unsigned comment added by 134.171.172.224 (talk) 16:43, 4 March 2013 (UTC)

Well, there's now a journal reference to it. * You should also identify yourself. 209.222.50.202 (talk) 15:50, 13 March 2013 (UTC)]

The above explanation is now moot - it's contained in the article referenced. Lehasa (talk) 17:31, 17 March 2013 (UTC)

This utterly ridiculous term is not used by anyone, and only featured in a Canada journal article. It is merely opinion. +99.9999% refer to it as a planetary nebula (plural planetary nebulae), and is recognised as such by the International Astronomical Union (IAU) I.e. The 'Division H Commission 34 WG Planetary Nebulae' at http://www.iau.org/science/scientific_bodies/working_groups/111/

Also the first two sentences are also wrong. I.e. It is not an emission nebula as they show mostly absorption lines. It is not said in the linked reference, while the statement "certain types of stars late in their life" in ambiguous and poorly defined.

Planetary nebula are abbreviated PN or plural PNe (not mentioned)

Also the central stars are called 'planetary nebula nucleus' or 'planetary nebulae nuclei' (or PNN or PNNe.) This is mentioned nowhere in the article.

This is supposed to be a 'Featured Article', but is plainly been junked because of a few who try and rework the facts or change the commonly used standard definition usage. Arianewiki1 (talk) 08:28, 9 July 2013 (UTC)

Video: Formation of a planetary nebula.

That video is atrociously poor. Besides the last frames where it's like BAMF nebula there isn't much in the way of illustrating the formation of ... anything in that, besides a cool corkscrew pattern. Surely there's a better video illustrating the formation of a planetary nebula out there? This would just confuse people about what they're even looking at as it looks nothing like any planetary nebula I've ever even seen? BaSH PR0MPT (talk) 09:17, 26 April 2013 (UTC)

Excellent Intro

The intro to this article is a model of simple elegance and readability. It does a very good job of informing the average reader in understandable terms while tending to make him or her want to know more about the subject - excellent work, whoever you are that put it into its present state. — Preceding unsigned comment added by BLZebubba (talk • contribs) 09:41, 2 May 2014 (UTC)

Congratulations on a great article. -- Charles Edwin Shipp (talk) 15:16, 30 May 2014 (UTC)

Actually, it needs far more work. There are still several unfounded statements and quite wrong facts. I've already corrected about dozen gross errors here. Arianewiki1 (talk) 06:43, 31 May 2014 (UTC)

Origin Section

This section in the article is an absolute mess. There is far to much verbiage and confusion with the facts, especially made worst by many unrelated statements. I cannot find even a few references related to much of this material. It needs to be rewritten to make more sense, and requires many more citations related to the material . Arianewiki1 (talk) 06:36, 31 May 2014 (UTC)

Removed a whole paragraph and its reference in this section. It is neither factual nor based on common evidence. It says stellar evolution is the cause of this, but most assign such events as to the binary nature of the central star. It is very theoretical idea. I.e. "It is likely that at least some planetary nebulae are composed of matter which was ejected from a binary star system during common-envelope (CE) evolution" , appearing in the paper "Planetary nebulae after common-envelope phases initiated by low-mass red giants" by Hall, P.D. et al. (2013) http://arxiv.org/pdf/1307.8023v2.pdf As this paper says; "there are more than 40 known PNe for which the compact source of ionizing photons is a member of a short- period binary star system. This sub-class could constitute 10–20 per cent of the total PNe population" Hence, the origins based on this removed paragraph would be the exception rather than the rule.

This paper confirms this by saying says; "This continues until the components merge to form a single star or until the envelope is ejected, to leave the remnant of the giant and its companion in a shorter period binary system. In this way, the material necessary for the PN (the ejected envelope) and the short-period binary system which may be able to illuminate the envelope are arranged. Despite its importance, our knowledge of CE evolution remains uncertain." Hence, the removal of this paragraph is completely justified.

Note: This paper also says the correct perspective on the origin of PNe, stating:

"Although we have yet to find any unambiguously identified post-red giant branch planetary nebulae, we should not discount this as a possible evolutionary interpretation. Remnants of post-asymptotic giant branch and post-red giant branch stars can be distinguished by the mass of the ionizing component, the abundances in the nebula and the photospheres of the hot remnants. Nebulae of this type would be useful to learn about common-envelope evolution and the formation of planetary nebula."

This Section needs to reflect this, and not be based on verified and now old mostly rejected ideas on PNe formation. Arianewiki1 (talk) 07:17, 31 May 2014 (UTC)

The Origin section here also needs to be related to Bipolar Planetary Nebula (BPNe) and the page https://en.wikipedia.org/Bipolar_nebula (which also required significant updating, too). Also most PNe are thought to be BPNe, which is stated across multiple references, including those given in the references in Wiki BPNe article!! Arianewiki1 (talk) 07:26, 31 May 2014 (UTC).

Lifetime Section

This whole section is taken from two sources written by the same author. It is both out of date and fits only one point of view. It desperately needs corrections and other reference sources. Worst the only mention of lifetime is in the last line, saying; "For a typical planetary nebula, about 10,000 years passes between its formation and recombination of the star." PNe can last between 10,000 and 30,000 years (many sources.) The last part makes little sense. "Recombination of the star". What does that actually mean? Arianewiki1 (talk) 08:58, 31 May 2014 (UTC)

Arianewiki1, if you feel this strongly about it it might be worth taking the article to FA review. It has been a very long time since it was promoted and 5 years since the last review. Sam Walton (talk) 11:16, 4 June 2014 (UTC)

I've taken your suggestion Sam Walton, and placed a FA Review. I have never done this before, so I might need your or others guidance here. (I hope I've haven't stuffed it up, so apologies if I've erred in some way. Thanks. Arianewiki1 (talk) 14:53, 7 June 2014 (UTC)

Protoplanetary disk

Should we explicitly mention protoplanetary disk, which this term might be confused with, in the lead section? - dcljr (talk) 19:55, 12 October 2016 (UTC)

No. Nothing to do with it. Arianewiki1 (talk) 05:50, 13 October 2016 (UTC)

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