molecular cloud

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Related to Molecular clouds: molecular gas

molecular cloud

n
(Astronomy) a cool dense interstellar region composed of a wide variety of molecules, mainly hydrogen, plus some dust, in which stars are forming
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It requires the special conditions found deep within frigid molecular clouds, where dust shields against destructive ultraviolet light and aids chemical reactions.
Molecular clouds of massive interstellar clouds within which the dust protects the water and other compounds from damaging radiation, and the conditions inside also promote chemical reactions.
In fact, the Orion Nebula, NGC 1662, and the giant molecular clouds around Lambda ([gamma]) Orionis are all roughly the same distance from the Sun.
Frozen films containing methane and oxygen used in these experiments further mimic a spacelike environment, since various types of ice (not just frozen water) form around dust grains in the dense and cold molecular clouds that exist in the interstellar medium.
Astrophysicists have granted Japanese artist Ryoichi Kurokawa the unique opportunity to explore data taken from molecular clouds in space - data which may hold the secrets behind the birth of stars.
And it's those dense molecular clouds that are the sites of future stars, planets and comets.
The 28 contributions describe techniques for finding answers about the fundamental questions of the physics and chemistry of interstellar gas, calculating rate coefficients for the gas-phase reactions and inelastic processes needed to model the chemistry of molecular clouds, determining absorption and photodissociation cross sections, and understanding surface reactions under interstellar conditions.
About 110 papers discuss such aspects as the evolution of giant molecular clouds in nearby galaxies, from large scale surveys of the galaxy to high resolution observations with ALMA, molecular gas properties and star formation in interacting galaxies, a study on the excitation mechanism of methyl formate in Orion KL using transitions in the vibrational excited states, and test observation of a new 100 GHz wave-band four-beam receiver system on the Nobeyama 45-meter telescope.
Computational models of stars forming within galaxies commonly zoom in on giant molecular clouds in a volume of interstellar space tens of light-years across with a resolution (ability to distinguish details) smaller than the size of our solar system.
Other trails lead from incomprehensibly (at the time) distant radio sources to the conclusion that black holes are fact, not speculation, whilst closer to home the radio signatures of complex molecules reveal the chemistry associated with Giant Molecular Clouds formed in the death of stars.
Infrared Dark Clouds (IRDC) are dense, cold molecular clouds that are likely to host massive star formation due to their physical and chemical properties.
Though star formation takes place in molecular clouds, the minimum requirements for it to occur at all are not completely clear and the efficiency of the processes in converting the available matter into stars is still a matter for investigation.

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