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The nebula is rich in carbon, and is a very interesting object for the study of carbon chemistry in dense molecular material exposed to strong ultraviolet radiation. [18] The spectrum of NGC 7027 contains fewer spectral lines from neutral molecules than is usual for planetary nebulae.
A protoplanetary disk forming in the Orion Nebula. The main problem in the physics of accretion disks is the generation of turbulence and the mechanism responsible for the high effective viscosity. [2] The turbulent viscosity is thought to be responsible for the transport of the mass to the central protostar and momentum to the periphery of the ...
NGC 6445, also known as the Little Gem Nebula or Box Nebula, is a planetary nebula in the constellation Sagittarius. It was discovered by William Herschel on May 28, 1786. [ 6 ] The distance of NGC 6445 is estimated to be slightly more than 1,000 parsecs based on the parallax measured by Gaia , which was measured at 0.9740 ± 0.3151 mas.
The Westbrook Nebula, a protoplanetary nebula. A protoplanetary nebula or preplanetary nebula [ 27 ] (PPN, plural PPNe) is an astronomical object which is at the short-lived episode during a star 's rapid evolution between the late asymptotic giant branch (LAGB) [a] phase and the subsequent planetary nebula (PN) phase.
Atomic physics plays a key role in astrophysics as astronomers' only information about a particular object comes through the light that it emits, and this light arises through atomic transitions. Molecular astrophysics , developed into a rigorous field of investigation by theoretical astrochemist Alexander Dalgarno beginning in 1967, concerns ...
NGC 6326, a planetary nebula with glowing wisps of outpouring gas that are lit up by a binary [3] central star. A planetary nebula is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. [4] The term "planetary nebula" is a misnomer because they are unrelated to ...
The Rosette Nebula, an example of a Strömgren sphere In theoretical astrophysics , there can be a sphere of ionized hydrogen (H II) around a young star of the spectral classes O or B . The theory was derived by Bengt Strömgren in 1937 and later named Strömgren sphere after him.
A molecular cloud, sometimes called a stellar nursery if star formation is occurring within, is a type of interstellar cloud of which the density and size permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen, H 2), and the formation of H II regions.