NGC 6751, also known as the Glowing Eye Nebula[2] or the Dandelion Puffball Nebula,^{[citation needed]} is a planetary nebula in the constellation Aquila. It is estimated to be about 6,500 light-years (2.0 kiloparsecs) away.[2]

NGC 6751

Emission nebula
Planetary nebula
A Hubble Space Telescope (HST) image of NGC 6751's inner bubble Credit: HST/NASA/ESA.
Observation data: J2000.0 epoch
Right ascension	19h 05m 55.6s[1]
Declination	−05° 59′ 32.9″[1]
Distance	6,500 ly   (2,000[2] pc)
Apparent magnitude (V)	11.9[3]
Apparent dimensions (V)	0.43′
Constellation	Aquila
Physical characteristics
Radius	0.4 ly
Absolute magnitude (V)	0.4
Designations	Glowing Eye Nebula, GSC 05140-03497, PK 029-05 1, PN Th 1-J, CSI-06-19031, HD 177656, PMN J1905-0559, PN Sa 2-382, EM* CDS 1043, HuLo 1, PN ARO 101, PN G029.2-05.9, GCRV 11549, IRAS 19032-0604, PN VV' 477, SCM 227, GSC2 S3002210353, 2MASX J19055556-0559327, PN VV 219, UCAC2 29903231
See also: Lists of nebulae

NGC 6751 was discovered by the astronomer Albert Marth on 20 July 1863.[4] John Louis Emil Dreyer, the compiler of the New General Catalogue, described the object as "pretty bright, small".[4] The object was assigned a duplicate designation, NGC 6748.[4][5]

The nebula was the subject of the winning picture in the 2009 Gemini School Astronomy Contest, in which Australian high school students competed to select an astronomical target to be imaged by Gemini.[6]

NGC 6751 is an easy telescopic target for deep-sky observers because its location is immediately southeast of the extremely red-colored cool carbon star V Aquilae.

Properties

NGC 6751, like all planetary nebulae was formed when a dying star threw off its outer layers of gas several thousand years ago. It is estimated to be around 0.8 light-years in diameter.[7]

NGC 6751 has a complex bipolar structure. There is a bright, inner bubble (shown in the photo), as well as two fainter halos. (The outer halo, with a radius of 50″ is extremely faint and is broken, while the inner halo with a radius of 27″ is roughly spherical).[2] On both the west and east sides of the inner shell, knots can be seen that are surrounded by faint “lobes”.[2] These lobes are actually a ring, and the eastern side is nearer than the western side.[2] As a whole, the system is approaching the Solar System with a heliocentric radial velocity of −31.7 km/s.[2]

The central star of the nebula has a similar spectrum to a Wolf–Rayet star (spectral type [WC4]),[1] and has an effective temperature of about 140,000 K and a radius of about 0.13 R_☉. It is losing mass at a rate of 1×10⁻⁶ M_☉ per year, and its surface composition is mostly helium and carbon.[2]

See also

• List of planetary nebulae

References

External links

• Media related to NGC 6751 at Wikimedia Commons
• NASA Astronomy Picture of the Day: Celebrating Hubble With NGC 6751 (16 April 2005)
• NGC 6751 seds.org
• NASA Astronomy Picture of the Day: NGC 6751: The Glowing Eye Nebula (13 March 2013)

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