Nebula in space - one of the wonders of the universe, is striking in its beauty.They are valuable not only visually appealing.Research nebulae helps scientists to clarify the functioning of the laws of space and objects, adjust the theory of the development of the universe and the life cycle of stars.Today, about these objects, we know a lot, but not all.
mixture of gas and dust
quite a long time, until the middle of the last century, were considered as star clusters, nebulae, distant from us at a considerable distance.The use of the spectroscope in 1860 helped to establish many of them are composed of gas and dust.English astronomer William Heggins revealed that the light from the nebula is different from the radiation coming from the usual stars.The range contains the first bright colored lines, interspersed with dark, while in the second case, these black bars are not observed.
Further investigation found that the nebulae of the Milky Way and other galaxies are mainly composed of a mixture of hot gas and dust.Often meet and similar cold forming.These clouds of interstellar gas also apply to fog.
Classification
Depending on the properties of the constituent elements of the nebula are several types.All of them are represented in large numbers in the vastness of space, and equally interesting for astronomers.Nebula emitting for whatever reason, the light received call or diffuse light.Opposing them on the basic parameters, of course, referred to as dark.Diffuse nebulae are of three types:
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reflective;
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equity;
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supernova remnant.
emission, in turn, are divided into areas of new star formation (H II), and planetary nebulae.All these types are characterized by certain properties that make them unique and worthy of scrutiny.
Areas of star formation
All emission nebula - a cloud of glowing gas of different forms.The main element of their constituent - hydrogen.Under the influence of the stars, in the center of the nebula, ionized and it collides with atoms heavier components of the cloud.The result of these processes is becoming a characteristic pinkish glow.
Eagle Nebula or M16 - a great representative of this type of object.Here is star-forming region, a lot of young, massive and hot stars.The Eagle Nebula - the place where the land is located is well-known space, Pillars of Creation.These gas clots formed under the influence of the stellar wind, is a zone of the star.By forming the light here causes compression of gas and dust columns by gravity.
Recently, scientists learned that enjoy the Pillars of Creation, we can still only a thousand years.Then they disappear.In fact, the destruction of the Pillars happened about 6,000 years ago due to the explosion of a supernova.However, the light from this region of space is to us about seven thousand years, so astronomers calculated an event for us - only in the future.
Planetary nebulae
name of the next type of glowing gas and dust clouds was introduced William Herschel.Planetary Nebula - the last stage of a star's life.Discharged luminary shell form a characteristic pattern.The nebula resembles a disk, usually around a planet when viewed through a small telescope it.Today we know more than a thousand such objects.
Planetary nebulae - part of the process of transformation of red giants in white dwarfs.In the center is a hot star formation, in its range similar luminaries with Class A. Its temperature reaches 125 000 K. Planetary nebulae are mostly relatively small size - 0.05 parsecs.Most of them are located in the center of our galaxy.
Mass gaseous envelope ejected star small.It is a few tenths of a similar parameter from the sun.The mixture of gas and dust is removed from the center of the nebula at speeds of up to 20 km / s.Shell has been around for 35 thousand years, and then it becomes rarefied and indiscernible.
Features
planetary nebula can be of various shapes.Basically, anyway, it is close to a sphere.Distinguish nebula round, ring-like dumbbells, irregular shape.The spectra of these space objects include the emission lines of glowing gas and the central star, and sometimes the absorption lines of the spectrum of light.
planetary nebula emits huge amounts of energy.It is significantly higher than the same indicator for the central star.The core of education because of its high temperature emits ultraviolet rays.They ionize the gas atoms.The particles are heated, rather they begin to emit UV visible rays.The spectrum and emission lines comprises characterizing the formation in general.
Cat's Eye Nebula
Nature - An expert in the creation of unexpected and beautiful forms.Noteworthy in this respect, a planetary nebula, because of the similarity named Cat's Eye (NGC 6543).It was discovered in 1786 and was the first that scientists have identified as a cloud of glowing gas.Cat's Eye Nebula is located in the constellation Draco, and has a very interesting complex structure.
It was formed about 100 years ago.Then the central star shed its shell and form concentric lines of gas and dust that are typical of the pattern of the object.Today is not clear until the end of the formation mechanism of the most expressive of the central structure of the nebula.The appearance of this figure is due to a well-located hotel in the heart of the nebula double star.However, while the data speaks in favor of this state of affairs, no.
temperature halo NGC 6543 is about 15,000 K. The core of the nebula warmed up to 80,000 K. The central star is several thousand times brighter than the sun.
colossal explosion
Massive stars often end their life cycle spectacular "special effects."Huge explosions on the power lead to the loss of luminary outer shells.They are removed from the center at a speed in excess of 10 000 km / s.Clash of moving matter from static causes a strong increase in the gas temperature.As a result, the particles begin to glow.Often, supernova remnants are not spherical education, which seems logical, and nebulae of various shapes.There is so because ejected at high speed stuff uneven forms clumps and clusters.
Next thousands of years ago
Perhaps the most famous supernova remnant - this is the Crab Nebula.The star that produced it exploded nearly a thousand years ago, in 1054.I managed to establish the exact date of the Chinese annals, where it is well described by flash in the sky.
characteristic pattern of the Crab Nebula is the gas ejected by the supernova, and are not yet fully mixed with interstellar matter.The object is located at a distance of 3300 light-years away and is continuously expanding at a speed of 120 km / s.
In the center of the Crab Nebula supernova remnant contains - a neutron star that emits a stream of electrons that generate continuous polarized radiation.
reflection nebula
Another type of space objects is made up of a mixture of cold gas and dust, unable to independently emit light.Reflection nebula illuminated by near objects.It may be a star or a similar diffuse education.The spectrum of the scattered light is the same as that of its source, but the blue light it predominates to an observer.
Very interesting this type of nebula associated with the star Merope.Light from the Pleiades for the past several million years flew by destroying the molecular cloud.As a result of the star nebula particles are arranged in a specific sequence and are drawn towards it.After some time (the exact date is unknown) Merope could completely destroy the cloud.
dark horse
diffuse formations often contrasted absorption nebula.The Milky Way galaxy has a lot of them.It is a very dense clouds of dust and gas that absorb light emission located behind them and reflection nebulae and stars.These cold space education are mainly composed of hydrogen atoms, although they meet and heavier elements.
great representative of this type - Horsehead Nebula.It is located in the constellation of Orion.The characteristic shape of the nebula is so similar to the horse's head, formed by the impact of the stellar wind and radiation.The object is clearly visible due to the fact that his background is bright emission formation.This Horsehead Nebula - only a small part of an extended absorbing clouds of dust and gas, virtually invisible.
Thanks to the Hubble telescope nebula, including planetary familiar today a wide range of people.Images regions of space where they are located, impress deeply and leave no one indifferent.
