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The Dumbbell Nebula (also known as Apple Core Nebula, Messier 27, M 27, or NGC 6853) is a planetary nebula in the constellation Vulpecula, at a distance of about 1,360 light years.
This object was the first planetary nebula to be discovered; by Charles Messier in 1764. At its brightness of visual magnitude 7.5 and its diameter of about 8 arcminutes, it is easily visible in binoculars, and a popular observing target in amateur telescopes.
Structure[]
The Dumbbell Nebula appears to be shaped like an 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 in the plane of the sky was no more than 2.3" per century. From this, an upper limit to the age of 14,600 yr may be determined. In 1970, Bohuski, Smith, and Weedman found an expansion velocity of 31 km/s. Given its semi-minor axis radius of 1.01 ly, this implies that the kinematic age of the nebula is some 9,800 years.[2][3]
Knots[]
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
. 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.[3] Template:-
Central star[]
The central star, a white dwarf, is estimated to have a radius which is Template:Val which gives it a size larger than any other known white dwarf.[4] The central star mass was estimated in 1999 by Napiwotzki to be Template:Val.[4]
See also[]
Template:Commons category
- Messier object
- List of Messier objects
- List of planetary nebulae
- New General Catalogue
Notes[]
- Template:Note labelRadius = distance × sin(angular size / 2) = Template:Val[5] * sin(8′.0 / 2) = Template:Val ly
- Template:Note labelSemi minor axis = distance × sin(minor axis size / 2) = Template:Val[5] × sin(5′.6 / 2) = Template:Val ly
- Template:Note labelKinematic age = semi-minor axis / expansion rate = Template:ValTemplate:Ref label ly / 31 km/s = Template:Val / 31[2] km/s = Template:Val s = Template:Val yr
- Template:Note label7.5 apparent magnitude - 5 × (log10(Template:Val distance) - 1) = Template:Val absolute magnitude
Template:Refend
References[]
- ↑ 1.0 1.1 1.2 1.3 Cite error: Invalid
<ref>tag; no text was provided for refs namedsimbad - ↑ 2.0 2.1 Cite error: Invalid
<ref>tag; no text was provided for refs namedODelletal2002 - ↑ 3.0 3.1 O'dell, C. R. (2003). "Knots in Planetary Nebulae". Revista Mexicana de Astronomía y Astrofísica, Serie de Conferencias 15: 29–33.
- ↑ 4.0 4.1 Benedict, G. Fritz (2003). "Astrometry with The Hubble Space Telescope: A Parallax of the Central Star of the Planetary Nebula NGC 6853". Astronomical Journal 126 (5): 2549–2556. DOI:10.1086/378603.
- ↑ 5.0 5.1 Cite error: Invalid
<ref>tag; no text was provided for refs namedHarrisetal2007
External links[]
- SEDS: Messier Object 27
- The Dumbbell Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
- M27 on astro-pics.com
- Szymanek, Nik. M27 – Dumbbell Nebula. Deep Sky Videos. Brady Haran.
- M27
- Dumbbell Nebula (M27) at Constellation Guide
Coordinates: Sky map 19h 59m 36.340s, 22° 43′ 16.09″ Template:Messier objects
