Thursday, June 20, 2019
Nebulae and their types
Nebula is an intergalactic cloud in reality, which has a negligible quantity of 90% hydrogen, 10% helium and other heavy elements. It is such a quaint gaseous cloud that is ever bright and attractive and sometimes dark is dark. They have played an important role in the evolution of the universe because these are the essential ingredients for the formation of stars and planets. These are seen in the night sky as a bright and shadowy shape, or in the form of a bright shadow in the background of any other published body.
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| Nebulae and their types |
Observational History
The history of inspecting nebulae is thousands of years old. In the second century AD, Ptolemy has mentioned five nebulae, 800 years after its mention, Abn al-Rahman Suri has mentioned a small cloud in place of the Devyani galaxy (Andromeda Galaxy). In 1610, Nicolas Claude Fabri de Peiresc inspected the Oraon Nebula with the telescope for the first time. After this, there was a flood of inspection of the Niharias in the eighteenth century by astronomers. Initially, all cloud-like structures were considered nebula. But in 1920 the work of Edwin P. Hubble found the real properties of the Niharias.
Classification of nebulae
In general, nebulae are divided into two categories, Galactic Nebulae and Extragalactic Nebulae. There is nothing known about external hydrocarbial nebulae, but galactic nebulae are divided into two subclasses, which are the diffuse nebulae and general nebulae.
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| Classification of nebulae |
Diffuse Nebulae
According to the name, it is the cloud of celestial gas which does not have any special normal shape. There are also two types of these nebulae, luminous and dark nebulae. Prakashan Niharika is a splendid, bright and easily visible scene. These nebulae are diffused as it is, it is found in irregular shape and in spiral arms of our galaxies.
Reflection Nebulae
Reflection Nebulae is a gaseous cloud that reflects the light of surrounding stars or emission of nebulae. These nebulae are published by the stars of B class which are highly bright in themselves but their temperature is less than 25000K, which is not enough to ionize the gas of these nebulae but scattering the light from the gas particles The nebula is able to make the gas particles bright.
Example: Witch Head Nebula.
Emission Nebulae
If a star before a B1 class is near the replica of the galaxy, then it has a diffuse emission nebula. The powerful ultraviolet radiation of these hot tires is so powerful that it is ionized to the nebula's gas by which it begins to emit visual light with the effect of fluorescence. This process is similar to the NiCon light or tube light.
There are two types of emission nebulae; HII area and supernova remnants
HII region
The HII region is a large cloud of low density whose gas has recently been ionized with the process of forming a star nearby. The ultraviolet radiation from the low-blue blue star emerges that they ionize the surrounding gas. This area has been named HII area because it contains abundant amounts of ionized hydrogen gas. The HII area can give birth to thousands of stars in the interval of some thousand million years. In the end, the supernova explosion and the stellar winds transmitted by nearby giant stars distinguish the gasoline of the HII region and in the end only survives the strings of the new birth.
Examples: Orion Nebula and Eagle Nebula
Supernova Remnants
The heavy giant stars end up in the form of supernovas, with an explosion in which the outer layers of stars are thrown in the intracurial area. The supernova remnant is the only nebula that is made of gaseous debris produced during the supernova eruption. During the supernova explosion in this gaseous nebula, apart from the debris of the outer layers of the star, the material collected by the Shockwave produced by the star from the interstellar medium is also collected. In these nebulae, visual invisible wavelength can be invisible but powerful X-ray and radio-radiation emission, which arises from reaction through the interstellar medium surrounding this nebula. The debris thrown from the supernova is slowed by friction and gravity while moving in the interstellar medium and the nucleus of the heavy substance present in this debris reacts through the interstellar medium. In this way, the stored material acts as raw material for the next generation of stars.
Examples: Crab Nebula
Dark Nebulae
Dark Nebula is a dense cloud of interstellar gas and dust that completely blocks the visible light of its backbone. These clouds appear darker because their microscopic particles have carbon dioxide and solid nitrogen layer, which absorbs the visible light wavelength of all the background light. The average density of these dust particles is 100-300 molecules / cubic cm and the temperature is 7-15K. These clouds are completely invisible but can be seen by microwave radiation emitted by their constituents.
Examples: Horsehead nebula
Planetary Nebulae
Planetary Nebulae, distinct from the irregularly-shaped emission nebulae, is a roughly streamlined emission nebula. In the middle of it there is a very high blue star, this center is called nebular center. It is basically a ring-shaped nebula that is made from a gaseous shell spreading from an old star. It is named Planetary because of its round shape like a planet but it has no relation to the planet. As the atmosphere of a large star gets scattered all over, then the ultraviolet radiation emitted from the brightest thermal nucleus of the star makes meonizing the material thrown out. The absorbed ultraviolet radiation energizes the neutral gas of the star, so that it appears as a brightly colored nebula.
Examples: The Eskimo Nebula
Author's message
Study of neoclassics is important for understanding the development of any galaxy. They are not only the starting point of the stars but also the last point of the stars. In this article we have discussed various sections of these nebulae, hope this article has inspired you to see the night sky from a new perspective.