Nebula - Formation

Formation

Many nebulae or stars form from the gravitational collapse of gas in the interstellar medium or ISM. As the material collapses under its own weight, massive stars may form in the center, and their ultraviolet radiation ionizes the surrounding gas, making it visible at optical wavelengths. Examples of these types of nebulae are the Rosette Nebula and the Pelican Nebula. The size of these nebulae, known as HII regions, varies depending on the size of the original cloud of gas. New stars are formed in the nebulas. The formed stars are sometimes known as a young, loose cluster.

Some nebulae are formed as the result of supernova explosions, the death throes of massive, short-lived stars. The materials thrown off from the supernova explosion are ionized by the energy and the compact object that it can produce. One of the best examples of this is the Crab Nebula, in Taurus. The supernova event was recorded in the year 1054 and is labelled SN 1054. The compact object that was created after the explosion lies in the center of the Crab Nebula and is a neutron star.

Other nebulae may form as planetary nebulae. This is the final stage of a low-mass star's life, like Earth's Sun. Stars with a mass up to 8–10 solar masses evolve into red giants and slowly lose their outer layers during pulsations in their atmospheres. When a star has lost enough material, its temperature increases and the ultraviolet radiation it emits can ionize the surrounding nebula that it has thrown off. The nebula is almost 97% hydrogen and 3% helium, plus trace amounts of other elements.

Read more about this topic:  Nebula

Other articles related to "formations, formation":

Chase County, Nebraska - Geography
... Rolling Sandhills formations are found in the north-central and southwestern areas of the county ... At Enders Dam this formation is found at a depth of 175 feet (53 m) below the valley floor ... The Ogallala Formation of Pliocene Age overlies the Pierre Shale ...
Gibbs Free Energy - Standard Energy Change of Formation
... The standard Gibbs free energy of formation of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of that substance from its component elements, at their ... states (oxygen gas, graphite, etc.) have 0 standard Gibbs free energy change of formation, as there is no change involved ...
1st Armoured Division (United Kingdom) - Formation
... As formed the Mobile Division was made up of the 1st and 2nd Light Armoured Brigades, the 1st Tank Brigade, artillery, engineers and signals ... Its paper strength was 620 armoured fighting vehicles, but seven eighths of these were reconnaissance vehicles, and of those some were being simulated by trucks ...
Gastrulation - In Amniotes - Formation of The Primitive Streak
... Formation of the primitive streak is reliant upon nodal signaling within the cells contributing to the primitive streak and BMP4 signaling from the extraembryonic tissue ... bilateral symmetry, determine the site of gastrulation and initiate germ layer formation ... migrate during the process of gastrulation and germ layer formation ...
French Second Republic - History - Formation
... This provisional government with Dupont de l'Eure as its president, consisted of Lamartine for foreign affairs, Crémieux for justice, Ledru-Rollin for the interior, Carnot for public instruction, Goudchaux for finance, Arago for the navy, and Burdeau for war ... Garnier-Pagès was mayor of Paris ...

Famous quotes containing the word formation:

    Out of my discomforts, which were small enough, grew one thing for which I have all my life been grateful—the formation of fixed habits of work.
    Elizabeth Stuart Phelps (1844–1911)

    I want you to consider this distinction as you go forward in life. Being male is not enough; being a man is a right to be earned and an honor to be cherished. I cannot tell you how to earn that right or deserve that honor. . . but I can tell you that the formation of your manhood must be a conscious act governed by the highest vision of the man you want to be.
    Kent Nerburn (20th century)

    Those who were skillful in Anatomy among the Ancients, concluded from the outward and inward Make of an Human Body, that it was the Work of a Being transcendently Wise and Powerful. As the World grew more enlightened in this Art, their Discoveries gave them fresh Opportunities of admiring the Conduct of Providence in the Formation of an Human Body.
    Joseph Addison (1672–1719)