Talk:M2-9

Ambiguous age/distance
How can something be 2100 light years away and be 1200 years old? The information given, no doubt, is intended to convey the message that the body was 1200 years old at 2100 years ago when the light we are receiving today set off on its journey to us, and that the object is 3300 years old today. Perhaps the wording can be made less ambiguous. I will leave that to someone else more knowledgeable than I.

Protoplanetary is not a type of planetary nebula
I'm pretty sure. JamesHoadley 16:27, 1 December 2005 (UTC)


 * Any citations one way or the other on this one? Wikipedia, in my experience seems to be big on notability. If you're not sure, and references aren't provided, you can: find references one way or the other yourself from RELIABLE sources, or insert a { { fact } } tag (no spaces) after the item that isn't sourced and might be controversial. Though, it shouldn't be wielded as a weapon (some folks tend to too liberally use the fact tag to try and slice/dice articles they disagree with; this is bad). Mgmirkin 15:36, 28 October 2006 (UTC)
 * I think the question was a bit vague... Are you asking whether protoplanetary nebula itself is a valid term? Or are you asking something more specific about its usage in the article? If you're asking whether it's a valid term, a very simple Google search for "Protoplanetary Nebula" brings up any number of references to the term. First three reasonably Notable pages:
 * Space.com article about Jupiter (uses the term in a solar system context)
 * Protoplanetary nebula (is a Wikipedia article.)
 * http://www.daviddarling.info/encyclopedia/P/protoplanetary_nebula.html (Defines the term.)
 * As opposed to [Planetary Nebula] as defined on the same site.
 * In this regard, the term is notable and in wide use, I believe. Did you have a more specific question about how the term has been used in this particular article? If so, please elucidate your concerns over the use of the term. Thanks. Mgmirkin 15:44, 28 October 2006 (UTC)


 * In reference to what I assume was the original question: A protoplanetary nebula is the term used for a nebula that is believed to be in the process of becoming a Planetary nebula. So, you are probably right in asserting that a Protoplanetary nebula =/= Planetary nebula. How does that impact this article? Is there a specific phrasing that is incorrect and requires changing? If so, please note it, and we can work together on a more accurate wording. Thx. Mgmirkin 15:53, 28 October 2006 (UTC)
 * Okay, will go off of another assumption here, and assume that you're referring to the line: "The bipolar planetary nebula has a particular form of twin lobes of material that emanates from a central star." I can see how this appears confusing when compared against the prior statement: "M2-9 (M does not stand for Messier object), or NGC 4567, is a protoplanetary nebula, which was discovered by Rudolph Minkowski in 1947." Original author or a subsequent editing author appears to have mixed up terms. I'll clarify this using slightly different wording to: "This bipolar nebula has a particular form of twin lobes of material that emanates from a central star." Hopefully, this should both resolve the issue and add value to the article by replacing the protoplanetary versus planetary nebula in the second instance with a reference to Bipolar nebula (a recent article created to discuss specifically this type of object; granted it's a stub in process). So, hopefully the confusion is gone now (I think the Wings of a Butterfly Nebula is generally agreed to be a Protoplanetary nebula rather than a Planetary nebula), and we have a link to an additional useful resource. Two birds with one stone! Mgmirkin 16:03, 28 October 2006 (UTC)
 * After further reading, I think that there may NOT be concensus on what constitutes a planetary nebula vs protoplanetary? In some instances, M2-9 is referred to as a planetary nebula indirectly (in a rough list of examples, but often with a note that it's not the 'typical' type, IE bipolar with bipolar outflow, etc.), and in others it's referred to directly as being a protoplanetary nebula. Can we get some definitive sources/citations one way, the other or both (with a note that there is controversy over what class of object this is)? Mgmirkin 17:22, 28 October 2006 (UTC)
 * In my opinion, astronomy has mistaken many distinctly similar objects as all belonging to different classes when in fact they really shouldn't be segregated so artificially. But my opinion doesn't really belong in the article, so I won't POV push. I just really think that astronomers need to more clearly demarcate exactly what classifies as one type of nebula versus another, with strict guidelines and make it clear which belongs to what, or if it can't be determined, perhaps the system need revising, or they need new guidelines. I mean, we see such similar structures on so many scales and in so many differrently classified objects, it's a comedy of errors in my opinion. But, as I said, that's just my opinion, so it won't go into the article. Mgmirkin 17:22, 28 October 2006 (UTC)


 * Have also removed from Category:Planetary nebulae, but added Category:Astronomy and Category:Nebulae. Removed 'See Also' entry for List of planetary nebulae, that can be reached from the Planetary nebulae page's 'See Also' section. Added to this page's 'See Also' section Planetary nebula and Protoplanetary nebula, for more info. Hopefully this all cleans things up a little bit, and makes the article slightly more useful. Though, now the 'See Also' section seems to be getting a bit lengthy. So, I'm thinking about taking out the references added before to other bipolar, possibly protoplanetary nebulae, and leaving those references in the Bipolar nebula article, then leaving the Bipolar nebula link in the 'See Also' section. This should tidy things up. Mgmirkin 16:14, 28 October 2006 (UTC)


 * Crud, just realized that the namespace might be wrong as well. This should probably be Protoplanetary Nebula M2-9, seeing as the Planetary Nebula article above says: "Infant planetary nebulae sometimes show evidence of a bipolar flow, as in the case of the Butterfly Nebula or Ant Nebula." I'm assuming that by "infant planetary nebulas" they mean Protoplanetary Nebulas {?} or nebulas in the process of moving from Nebula to Planetary Nebula (again assuming that the intermediate or infant step is the Protoplanetary Nebula)? Once again, I think this reinforces the need to merge Planetary Nebula M2-9 and Wings of a Butterfly Nebula and decide the issue of what namespace should be used as well as what an accurate namespace for this object actually is, and what stage it is in. Is this a protoplanetary nebula with bipolar formatio nand bipolar outflow, or is this a planetary nebula? I thought planetary nebulae were supposed to be large round nebulae. The Planetary nebula article has this to say:
 * "A planetary nebula is an astronomical object consisting of a glowing shell of gas and plasma formed by certain types of stars at the end of their lives. They are in fact unrelated to planets; the name originates from a supposed similarity in appearance to giant planets."
 * "The first planetary nebula discovered was the Dumbbell Nebula in the constellation of Vulpecula, observed by Charles Messier in 1764 and listed as M27 in his catalogue of nebulous objects. To early observers with low-resolution telescopes, M27 and subsequently discovered planetary nebulae somewhat resembled the gas giants, and William Herschel, discoverer of Uranus, eventually coined the term 'planetary nebula' for them, although, as we now know, they are very different from planets."
 * "Generally speaking, planetary nebulae are symmetrical and approximately spherical, but a wide variety of shapes exist with some very complex forms seen. Approximately 10% of planetary nebulae are strongly bipolar, and a small number are asymmetric.  One is even rectangular.  The reason for the huge variety of shapes is not fully understood, but may be caused by gravitational interactions with companion stars if the central stars are double stars.  Another possibility is that planets disrupt the flow of material away from the star as the nebula forms.  In January 2005, astronomers announced the first detection of magnetic fields around the central stars of two planetary nebulae, and hypothesised that the fields might be partly or wholly responsible for their remarkable shapes . [[Image:Diverse planetary nebulae.jpg|thumb|600px|center|Some of the huge range of shapes that planetary nebulae can take.  Even the spherical ones can be amazingly complex.  The nebulae here are (l to r) the [[Spirograph Nebula]], the Hourglass Nebula, the Eskimo Nebula, the Ant Nebula and the Ring Nebula]]"
 * So, I guess the question becomes one of whether this is a Protoplanetary Nebula or a Planetary Nebula, and what defining characteristics demarcate the two?? That should probably be figured in to figuring out which namespace is accurate, and deciding which terminology to use in the article Planetary vs Protoplanetary? Mgmirkin 17:13, 28 October 2006 (UTC)

Merge? (Wings of a Butterfly Nebula)
Okay, let's discuss merging Wings of a Butterfly Nebula with this article. Both appear to have good information. Both appear to describe the same object. We should decide which namespace take precedent, and/or is used more commonly, and proceed from there. Frankly I've heard it referred to as the Wings of a Butterfly Nebula or shortened to Butterfly Nebula. However, in Wikipedia: Butterfly Nebula actually redirects to yet another DIFFERENT butterfly nebula. So, we might want to talk with the authors of that page on a disambiguation page so that different butterfly nebulas don't get confused on wikipedia?

Anyway, I also note that Twin Jet Nebula also redirects here, as does M2-9. So, for that reason, it seems like this should be where things get merged or redirected to. However, I don't know if M2-9 or Wings of a Butterfly Nebula is more common or correct usage. I see nebula pages all over wikipedia using different standards for naming. Some name based on NGC number, some based on CRL #, some based on the colloquial names. This seems confusing for anyone trying to look up info. But that's maybe a topic for a different and broader discussion.

Anyway, I've put a proposed merger tag on both pages for discussion. So, let's discuss. :) Mgmirkin 19:57, 25 October 2006 (UTC)


 * I'm just going to wager from the lack of discussion that nobody's really watching the article(s), so I'll Be Bold and merge it myself... Will simply copy/paste the Wings of a Butterfly Nebula full text into this article, then edit to taste. Mgmirkin 01:51, 4 November 2006 (UTC)


 * Here's a copy of what was over there:


 * VVVVV
 * The Wings of a Butterfly Nebula (also known by the designation M2-9 and by the name Twin Jet Nebula) is about 2,100 light-years away from Earth in the direction of the constellation Monoceros. It represents the spectacular "last gasp" of a binary star system at the nebula's center . One component of this binary is the hot core of a star that reached the end of its main-sequence life cycle, ejected most of its outer layers and became a red giant, and is now contracting into a white dwarf. This central star is one of a very closely orbiting pair - the smaller star may even have been engulfed by the other's expanding stellar atmosphere.


 * The resulting interaction has created the stunning protoplanetary nebula. Astronomers theorize that the gravity of one star pulls some of the gas from the surface of the other and flings it into a thin, dense disk extending into space . Such a disk can successfully account for the jet-exhaust-like appearance of M2-9.


 * The nebula has inflated dramatically due to a fast stellar wind, blowing out into the surrounding disk and inflating the large, wispy hourglass-shaped wings perpendicular to the disk. These wings produce the butterfly appearance when seen in projection. The total diameter of the nebula is about one-third of a light-year, or 2 trillion miles.


 * Early in its life the main component of the system was believed to be a sun-like star.
 * ^^^^^ Mgmirkin 01:51, 4 November 2006 (UTC)


 * Okay, I've finished merging and re-ordering. Hopefully things make more sense now. I think the article's a bit fuller now that the articles have been merged. Wouldn't hurt to add more info and sectionalize it: history, structure, current theory on formation, etc. I don't have time for it right now. But if someone else wants to Be Bold, be my guest. Mgmirkin 02:13, 4 November 2006 (UTC)

Minor cleanup...
I've re-ordered the introductory paragraph slightly such that it's now two shorter paragraphs. The first deals with its naming, the second with its discovery and imaging. I'll probably merge Wings of a Butterfly Nebula here shortly, since there's no talk thusfar, and it seems like a fairly uncontroversial move. Though I'm still unsure of the namespace though. looking through NASA's ADS system, it seems as though M2-9 is alternately referred to as a Protoplanetary nebula and as a Planetary nebula. This seems like it could be comes a point oif contention. Anyone know definitively which category this nebula falls under? Or is tehre even general consensus in the scientific community as to what defines one versus the other and/or where M2-9 stands as far as categorization? Seems confusing when different articles refer to it differently. Regardless, I'll merge Wings of a Butterfly Nebula here shortly, and namespace issues can be worked out later. Mgmirkin 01:42, 4 November 2006 (UTC)


 * Edited the merged sections from the old Wings of a Butterfly Nebula article. So, hopefully things flow better now. It starts out with naming, then discovery and imaging. What scientists imagine is at the center of the nebula and how the lobes are formed. I'd appreciate someone tracking down a few articles that either support or don't support the items with { { fact } } tags. Not necessarily looking to remove them, just satisfy notability for the statements (I find them controversial, personally, as I think a lot of mainstream science has it wrong on what these are, but if someone can find citations that someone thinks these statements are right/notable, I'm happy to leave them in). Mgmirkin 02:18, 4 November 2006 (UTC)


 * Edited out reference to NGC 4567, since that is referring to the Butterfly Galaxies not to any of the nebulas referred to as Butterfly Nebula. Created a disambiguation page for Butterfly Nebula (disambiguation) to help ease confusion. I've made it so that Butterfly Nebula redirects here, but have included a { {Redirect | Butterfly Nebula } } tag so that there's a link to the disambiguation page in case someone was looking for one of the "Butterfly Nebulas"... Mgmirkin 03:22, 4 November 2006 (UTC)

What do the numbers in the name M2-9 refer to?
I'm puzzled by the name M2-9. It looks like a mislabeled Messier object at first. It doesn't seem that Minkowski discovered a whole lot of objects, such that they would need a two-level naming scheme. The numbers are single digits, and don't seem to label the RA Dec or that sort of thing, though I haven't checked in other coordinate systems. So what's up? ★NealMcB★ (talk) 17:05, 15 September 2013 (UTC)
 * This SIMBAD dictionary entry shows PN M 2-NN covers a set of 56 nebulae listed in Minkowski's 1947 letter. -84user (talk) 09:35, 16 September 2013 (UTC)