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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. A blue ...
In many emission nebulae, an entire cluster of young stars is contributing energy. [1] [2] Stars that are hotter than 25,000 K generally emit enough ionizing ultraviolet radiation (wavelength shorter than 91.2 nm) to cause the emission nebulae around them to be brighter than the reflection nebulae. [3]
Diffuse nebulae can be divided into emission nebulae, reflection nebulae and dark nebulae. Visible light nebulae may be divided into emission nebulae, which emit spectral line radiation from excited or ionized gas (mostly ionized hydrogen ); [ 25 ] they are often called H II regions , H II referring to ionized hydrogen), and reflection nebulae ...
This is a list of diffuse nebulae. Most nebulae are diffuse , meaning that they do not have well-defined boundaries. Types of diffuse nebulae include emission nebulae and reflection nebulae .
Reflection nebulae, as their name suggest, reflect the light of nearby stars. Their spectra are the same as the stars surrounding them, though the light is bluer; shorter wavelengths scatter better than longer wavelengths. Emission nebulae emit light at specific wavelengths depending on their chemical composition. [34]
Since the definition is objects that are not Solar System objects or individual stars, examples include: [10] Black holes [11] and active galactic nuclei [12] Nebulae. Bright nebulae. Emission nebulae; Reflection nebulae; H II regions; Diffuse ionized gas; Planetary nebulae; Supernova remnants; Dark nebulae [13] Galaxies [14] Star clusters ...
This H II region includes the reflection and emission nebulae IC 59 and IC 63. [4] Both nebulae have a cometary shape, with IC 63 being the brighter of the two. [6] The difference in appearance between the two nebulae is a consequence of their physical distance from γ Cas. IC 63 displays a well-defined ionization front, while this is lacking ...
A dark nebula or absorption nebula is a type of interstellar cloud, particularly molecular clouds, that is so dense that it obscures the visible wavelengths of light from objects behind it, such as background stars and emission or reflection nebulae.