Dumbbell Nebula

Dumbbell Nebula

Nebula
ESO image showing extended structure and central star
Observation data: J2000 epoch
Right ascension	19^h 59^m 36.340^s[1]
Declination	+22° 43′ 16.09″[1]
Distance	1360+160 −212 ly (417+49 −65 pc)[2][3] ly
Apparent magnitude (V)	7.5[1]
Apparent dimensions (V)	8′.0 × 5′.6[4]
Constellation	Vulpecula
Physical characteristics
Radius	1.44+0.21 −0.16 ly^[a] ly
Absolute magnitude (V)	−0.6+0.4 −0.3^[d]
Notable features	Central star radius is largest known for a white dwarf.
Designations	NGC 6853,[1] M 27,[1] Diabolo Nebula,[1] Dumb-Bell Nebula,[1]

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,^[5] and a popular observing target in amateur telescopes.

Structure

Picture of M27 processed and combined using IRAF and MaxIm DL by Mohamad Abbas

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.^[4][6]

Knots

Closeup of knots in M 27 taken by the Hubble Space Telescope

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.^[6]

Central star

The central star, a white dwarf, is estimated to have a radius which is 0.055±0.02 R_☉ which gives it a size larger than any other known white dwarf.^[2] The central star mass was estimated in 1999 by Napiwotzki to be 0.56±0.01 M_☉.^[2]

Gallery

• 
  M27 in Vulpecula constellation
• 
  Image from the Spitzer Space Telescope
• 
  Image from a ground-based telescope at Westview Observatory in Cridersville, OH

See also

• Messier object
• List of Messier objects
• List of planetary nebulae
• New General Catalogue

Notes

1. ^{^} Radius = distance × sin(angular size / 2) = 1240+180
   −140^[3] * sin(8′.0 / 2) = 1.44+0.21
   −0.16 ly
2. ^{^} Semi minor axis = distance × sin(minor axis size / 2) = 1240+180
   −140^[3] × sin(5′.6 / 2) = 1.01+0.15
   −0.11 ly
3. ^{^} Kinematic age = semi-minor axis / expansion rate = 1.01+0.15
   −0.11^[b] ly / 31 km/s = 9.56+1.42
   −1.04×10¹² km / 31^[4] km/s = 3.08+0.46
   −0.34×10¹¹ s = 9800+1500
   −1100 yr
4. ^{^} 7.5 apparent magnitude - 5 × (log₁₀(420+50
   −70 pc distance) - 1) = −0.6+0.4
   −0.3 absolute magnitude

References

1. "SIMBAD Astronomical Database". Results for M 27. Retrieved 2007-01-03.
2. Benedict, G. Fritz; McArthur, B. E.; Fredrick, L. W.; Harrison, T. E.; et al. (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. arXiv:astro-ph/0307449. Bibcode:2003AJ....126.2549B. doi:10.1086/378603.
3. Harris, Hugh C.; Dahn, Conard C.; Canzian, Blaise; Guetter, Harry H.; et al. (2007). "Trigonometric Parallaxes of Central Stars of Planetary Nebulae". Astronomical Journal. 133 (2): 631–638. arXiv:astro-ph/0611543. Bibcode:2007AJ....133..631H. doi:10.1086/510348.
4. O'Dell, C. R.; Balick, B.; Hajian, A. R.; Henney, W. J.; et al. (2002). "Knots in Nearby Planetary Nebulae". Astronomical Journal. 123 (6): 3329–3347. Bibcode:2002AJ....123.3329O. doi:10.1086/340726.
5. https://messierobjects101.com/messier-object-m27-dumbbell-nebula/
6. O'dell, C. R.; Balick, B.; Hajian, A. R.; Henney, W. J.; et al. (2003). "Knots in Planetary Nebulae". Revista Mexicana de Astronomía y Astrofísica, Serie de Conferencias. 15: 29–33. Bibcode:2003RMxAC..15...29O.

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; Merrifield, Michael. "M27 – Dumbbell Nebula". Deep Sky Videos. Brady Haran.
• M27
• Dumbbell Nebula (M27) at Constellation Guide

Coordinates: 19^h 59^m 36.340^s, 22° 43′ 16.09″