View source for Dumbbell Nebula

{{Short description|Planetary nebula in the constellation Vulpecula}}
{{Redirect|M 27|other uses|M27 (disambiguation){{!}}M27}}
{{Infobox Planetary nebula
| image   = [[File:M27 - Noao-m27.jpg|300 px]]
| caption = Dumbbell Nebula (Messier 27) in Vulpecula
| name    = Dumbbell Nebula
| epoch   = [[J2000]]
| ra      = {{RA|19|59|36.319}}<ref name="simbad">
{{cite simbad
 | title=M 27
 | access-date=2023-12-31
}}</ref>
| type    = Planetary
| dec     = {{DEC|+22|43|16.312}}<ref name="simbad"/>
| dist_pc = {{val|389|+15|-6}}<ref name=simbad/>
| appmag_v = 7.4<ref>{{cite web |url=http://www.messier.seds.org/m/m027.html |title=Messier 27 |access-date=21 July 2024 |website=SEDS Messier Catalog}}</ref>
| size_v   = 8.0′ × 5.6′<ref name="ODelletal2002" />
| constellation  = [[Vulpecula]]
| radius_ly = {{val|1.44|+0.21|-0.16}}{{Ref label|A|a|none}}
| absmag_v  = {{val|-0.6|+0.4|-0.3}}{{Ref label|D|d|none}}
| notes     = Central star radius is among the largest<br />known for a white dwarf.
| names     = [[New General Catalogue|NGC]] 6853,<ref name="simbad"/> [[Messier object|M]] 27,<ref name="simbad"/><br />Diabolo Nebula,<ref name="simbad"/><br />Dumb-Bell Nebula,<ref name="simbad"/>
}}

The '''Dumbbell Nebula''' (also known as the '''Apple Core Nebula''', '''Messier 27''', and '''NGC 6853''') is a [[planetary nebula]] (nebulosity surrounding a white dwarf) in the [[constellation]] [[Vulpecula]], at a distance of about 1360 [[light-year]]s.<ref name=simbad/> It was the first such nebula to be discovered, by [[Charles Messier]] in 1764. At its brightness of [[visual magnitude]] 7.5 and diameter of about 8 [[arcminute]]s, it is easily visible in binoculars<ref>{{Cite web | url=https://messierobjects101.com/messier-object-m27-dumbbell-nebula/ | title=M 27| date=2016-10-15}}</ref> and is a popular observing target in [[amateur astronomy|amateur telescopes]].

The Dumbbell Nebula appears shaped like a [[prolate spheroid]] and is viewed from our perspective along the plane of its equator. In 1992, Moreno-Corral [[et al.]] computed that its rate of expansion angularly was, viewed from our distance, no more than {{val|2.3|ul=arcseconds}} (″) per century. From this, an upper limit to the age of 14,600 years may be determined. In 1970, Bohuski, Smith, and Weedman found an expansion velocity of {{val|31|ul=km/s}}. Given its [[semi-minor axis]] radius of {{val|1.01|ul=ly}}, this implies that the kinematic age of the nebula is 9,800 years.<ref name="ODelletal2002">
{{cite journal
 | author=O'Dell, C. R.
 | display-authors=4
 | author2=Balick, B.
 | author3=Hajian, A. R.
 | author4=Henney, W. J.
 | author5=Burkert, A.
 | date=2002
 | title=Knots in Nearby Planetary Nebulae
 | journal=[[Astronomical Journal]]
 | volume=123 | issue=6 | pages=3329–3347
 | bibcode=2002AJ....123.3329O
 | doi=10.1086/340726
| doi-access=free
 }}</ref><ref name="ODelletal2003">
{{cite journal
 | author=O'dell, C. R.
 | display-authors=4
 | author2=Balick, B.
 | author3=Hajian, A. R.
 | author4=Henney, W. J.
 | author5=Burkert, A.
 | date=2003
 | title=Knots in Planetary Nebulae
 | journal=Revista Mexicana de Astronomía y Astrofísica, Serie de Conferencias
 | volume=15 | pages=29–33
 | bibcode=2003RMxAC..15...29O
 }}</ref>

Like many nearby planetary nebulae, the Dumbbell contains knots. Its central region is marked by a pattern of dark and bright cusped knots and their associated dark tails (see picture). The knots vary in appearance from symmetric objects with tails to rather irregular tail-less objects. Similarly to the [[Helix Nebula]] and the [[Eskimo Nebula]], the heads of the knots have bright cusps which are local [[photoionization]] fronts.<ref name="ODelletal2003" />

The central star, a [[white dwarf]] progenitor, is estimated to have a radius which is {{val|0.055|0.02|ul=R_solar}} (0.13 light seconds) which gives it a size larger than most other known white dwarfs.<ref name="Benedictetal2003">
{{cite journal
 | author=Benedict, G. Fritz
 | display-authors=4
 | author2=McArthur, B. E.
 | author3=Fredrick, L. W.
 | author4=Harrison, T. E.
 | author5=Skrutskie, M. F.
 | author6=Slesnick, C. L.
 | author7=Rhee, J.
 | author8=Patterson, R. J.
 | author9=Nelan, E.
 | author10=Jefferys, W. H.
 | author11=van Altena, W.
 | author12=Montemayor, T.
 | author13=Shelus, P. J.
 | author14=Franz, O. G.
 | author15=Wasserman, L. H.
 | author16=Hemenway, P. D.
 | author17=Duncombe, R. L.
 | author18=Story, D.
 | author19=Whipple, A. L.
 | author20=Bradley, A. J.
 | date=2003
 | title=Astrometry with The Hubble Space Telescope: A Parallax of the Central Star of the Planetary Nebula NGC 6853
 | journal=[[Astronomical Journal]]
 | volume=126 | issue=5 | pages=2549–2556
 | bibcode=2003AJ....126.2549B
 | doi=10.1086/378603
|arxiv = astro-ph/0307449 | s2cid=8562211
 }}</ref> Its mass was estimated in 1999 by Napiwotzki to be {{val|0.56|0.01|ul=M_solar}}.<ref name="Benedictetal2003" />

== Appearance ==
{| class=wikitable align=center width=340
|[[File:Vulpecula IAU.svg|330px]]<BR>Constellation Vulpecula
|-
|[[File:Messier27-starmap.png|330px]]<BR>Location map
|}
The Dumbbell nebula is located in the faint constellation [[Vulpecula]], within the [[Summer Triangle]]. It is located in the sky a few degrees north of [[Gamma Sagittae|γ Sagittae]], near the star [[14 Vulpeculae]]. It is bright enough to be  seen in [[binoculars]].

==See also==
* [[Messier object]]
* [[List of Messier objects]]
* [[List of planetary nebulae]]
* [[New General Catalogue]]

== Notes ==
{{refbegin}}
<ol type="a">
<li>{{Note label|A|a|none}}Radius = distance × sin(angular size / 2) = {{val|1240|+180|-140}}<ref name="Harrisetal2007">
{{cite journal
 | author = Harris, Hugh C.
 | display-authors = 4
 | author2 = Dahn, Conard C.
 | author3 = Canzian, Blaise
 | author4 = Guetter, Harry H.
 | author5 = Leggett, S. K.
 | author6 = Levine, Stephen E.
 | author7 = Luginbuhl, Christian B.
 | author8 = Monet, Alice K. B.
 | author9 = Monet, David G.
 | author10 = Pier, Jeffrey R.
 | author11 = Stone, Ronald C.
 | author12 = Tilleman, Trudy
 | author13 = Vrba, Frederick J.
 | author14 = Walker, Richard L.
 | title = Trigonometric Parallaxes of Central Stars of Planetary Nebulae
 | date = 2007
 | journal = [[Astronomical Journal]]
 | volume = 133 | issue = 2 | pages = 631–638
 | bibcode = 2007AJ....133..631H
 | doi = 10.1086/510348
|arxiv = astro-ph/0611543 | s2cid = 18261027
 }}</ref> * sin(8′.0 / 2) = {{val|1.44|+0.21|-0.16}} ly</li>
<li>{{Note label|B|b|none}}Semi minor axis = distance × sin(minor axis size / 2) = {{val|1240|+180|-140}}<ref name="Harrisetal2007" /> × sin(5′.6 / 2) = {{val|1.01|+0.15|-0.11}} ly</li>
<li>{{Note label|C|c|none}}Kinematic age = semi-minor axis / expansion rate = {{val|1.01|+0.15|-0.11}}{{Ref label|B|b|none}} ly / 31&nbsp;km/s = {{val|9.56|+1.42|-1.04|e=12|u=km}} / 31<ref name="ODelletal2002" /> km/s = {{val|3.08|+0.46|-0.34|e=11}} s = {{val|9800|+1500|-1100}} yr</li>
<li>{{Note label|D|d|none}}7.5 apparent magnitude - 5 × (log<sub>10</sub>({{val|420|+50|-70|u=pc}} distance) - 1) = {{val|-0.6|+0.4|-0.3}} absolute magnitude</li>
</ol>
{{refend}}

==References==
{{Reflist|30em}}

==External links==
{{commons category|Dumbbell Nebula}}
* [http://www.messier.seds.org/m/m027.html SEDS: Messier Object 27]
* {{WikiSky|name=The Dumbbell Nebula}}
* [http://www.astro-pics.com/27plm.htm M27 on astro-pics.com]
* {{cite web|title=M27 – Dumbbell Nebula|url=http://www.deepskyvideos.com/videos/messier/M27_planetary_nebula.html|work=Deep Sky Videos|publisher=[[Brady Haran]]|author=Szymanek, Nik|author-link=Nik Szymanek|author2=Merrifield, Michael}}
* [http://www.dsi-astronomie.de/M27AO8.html M27]


{{Messier objects}}
{{Ngc70}}
{{Vulpecula}}
{{Portal bar|Astronomy|Stars|Outer space}}
{{Sky|19|59|36.340||22|43|16.09|1360}}
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{{DEFAULTSORT:Dumbbell Nebula}}
[[Category:Planetary nebulae]]
[[Category:Vulpecula]]
[[Category:Messier objects]]
[[Category:NGC objects]]
[[Category:Orion–Cygnus Arm]]
[[Category:Astronomical objects discovered in 1764|17640712]]
[[Category:Discoveries by Charles Messier]]