NGC 6751, also known as the Glowing Eye Nebula,
[ is a planetary nebula in the ]constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the e ...
Aquila
Aquila may refer to:
Arts, entertainment, and media
* ''Aquila'', a series of books by S.P. Somtow
* ''Aquila'', a 1997 book by Andrew Norriss
* ''Aquila'' (children's magazine), a UK-based children's magazine
* ''Aquila'' (journal), an or ...
. It is estimated to be about 6,500 light-year
A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...
s (2.0 kilo parsecs) away.New General Catalogue
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and ...
, described the object as "pretty bright, small".[ The object was assigned a duplicate designation, NGC 6748.]carbon star
A carbon star (C-type star) is typically an asymptotic giant branch star, a luminous red giant, whose atmosphere contains more carbon than oxygen. The two elements combine in the upper layers of the star, forming carbon monoxide, which consumes mos ...
V Aquilae.
Properties
NGC 6751, like all planetary nebulae was formed when a dying star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
threw off its outer layers of gas several thousand years ago. It is estimated to be around 0.8 light-years in diameter.
NGC 6751 has a complex bipolar
Bipolar may refer to:
Astronomy
* Bipolar nebula, a distinctive nebular formation
* Bipolar outflow, two continuous flows of gas from the poles of a star
Mathematics
* Bipolar coordinates, a two-dimensional orthogonal coordinate system
* 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).[ On both the west and east sides of the inner shell, knots can be seen that are surrounded by faint "lobes".][ These lobes are actually a ring, and the eastern side is nearer than the western side.][ As a whole, the system is approaching the Solar System with a heliocentric ]radial velocity
The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...
of −31.7 km/s.[
The central star of the nebula has a similar spectrum to a Wolf–Rayet star (spectral type C4,][ and has an ]effective temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...
of about 140,000 K and a radius of about . It is losing mass at a rate of per year, and its surface composition is mostly helium and carbon.[
The winning image of the 2009 Gemini Astronomy Contest shows a nebula at the top left of NGC 6751.]
See also
* List of planetary nebulae
References
External links
*
*
NGC 6751
seds.org
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Planetary nebulae
6751
Aquila (constellation)
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