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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 planetary nebula is a type of emission nebula consisting of an expanding, ... [68] and their interactions with ionized gas could explain some planetary nebulae shapes.
An emission nebula is a nebula formed of ionized gases that emit light of various wavelengths. The most common source of ionization is high-energy ultraviolet photons emitted from a nearby hot star .
The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion, and is known as the middle "star" in the "sword" of Orion.
The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems). It suggests the Solar System is formed from gas and dust orbiting the Sun which clumped up together to form the planets.
The Horsehead Nebula (also known as Barnard 33 or B33) is a small dark nebula in the constellation Orion. [2] The nebula is located just to the south of Alnitak , the easternmost star of Orion's Belt , and is part of the much larger Orion molecular cloud complex .
Below, registered dietitians and a doctor explain the shelf-life of vitamins and how it varies, plus how to store your vitamins for optimal use and the safety risks of consuming vitamins when they ...
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.