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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) phase and the subsequent planetary nebula (PN) phase.
A protoplanetary nebula or preplanetary nebula [1] (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) phase and the subsequent planetary nebula (PN) phase. A PPN emits strongly in infrared radiation, and is a kind of reflection nebula.
Nebulae become visible if the gas glows, or if the cloud reflects starlight or obscures light from more distant objects. The catalogues that it may refer to: Catalogue des nébuleuses et des amas d'étoiles (Messier "M" catalogue) first published 1771; Catalogue of Nebulae and Clusters of Stars (William Herschel 'CN'/"H" catalogue) first ...
The Orion Nebula is part of a much larger nebula known as the Orion molecular cloud complex, which extends throughout the constellation of Orion and includes Barnard's Loop, the Horsehead Nebula, M43, M78, and the Flame Nebula. Stars are forming throughout the entire Cloud Complex, but most of the young stars are concentrated in dense clusters ...
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 ...
In 1852 Stephen Alexander supposed that Milky Way is also a spiral nebula. [35] The question of whether such objects were separate galaxies independent of the Milky Way, or a type of nebula existing within our own galaxy, was the subject of the Great Debate of 1920, between Heber Curtis of Lick Observatory and Harlow Shapley of Mount Wilson ...
The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. [4]It constitutes the visible portions of the Cygnus Loop, [5] a supernova remnant, many portions of which have acquired their own individual names and catalogue identifiers.
Reflection nebula are usually blue because the scattering is more efficient for blue light than red (this is the same scattering process that gives us blue skies and red sunsets). Reflection nebulae and emission nebulae are often seen together and are sometimes both referred to as diffuse nebulae. Some 500 reflection nebulae are known.