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What is a nebula?

 Automatic translationAutomatic translation Category: nebulas
Updated June 01, 2013

From Latin ' nebula ' which wants to say cloud, clouds of gas and dusts in the middle of stars, nebulas are at the same moment active crèches and cemeteries of stars. These magnificence of the sky are enlightened by the stars which they contain or by stars situated behind them. It is the most beautiful images of astronomy that we can obtain at present.
Nebulas make us admire in the field of the telescope of magnificent conglomerations of stars and gas flooding the sky. More the telescope is powerful more the images are magnificent.
Only long poses will reveal the whole palette of colors in particular the surprising pink color of the hydrogen. William Hershel discovered the dark nebulas, the clouds of gas and dusts without star, too dense to allow to pass the light of stars situated behind.


Nota: ESA (European Space Agency)
European Southern Observatory (ESO, the European Organization for Astronomical Research in the Southern Hemisphere.
NGC (New General Catalog) is one of the best known catalogs in the field of amateur astronomy with the Messier catalog.

Image: In one image every splendors of the constellation Orion: (from left to right) the Flame Nebula and its dark channels (NGC 2024), the head of Horse or Barnard 33, NGC 1977 (purple and blue) and the Orion Nebula or M 42 (red-orange center right).


Nebula N81


N 81 is a cloud of reddening gas, which shelters from young and brilliant stud.
The reddish glow of this nebula is the result of the ultraviolet radiation emitted by its most brilliant two stars, 300 000 times as brilliant as the Sun. N 81 is in the Small Cloud of Magellan, itself small satellite galaxy of the Milky Way.
The recent and massive stars inside N 81 lose their matter very quickly, creating powerful solar winds and shock waves drilling the cocoon of the outside nebula. The most brilliant both stars seen on the image of Hubble under the shape of a pair very moved closer near the center of N 81 emit strong ultraviolet radiations, returning the fluorescent nebula.
The images sent by Hubble show " that a heap of young massive stars is destroying its native cocoon.


The small Cloud of Magellan (PNM), named according to the name of the explorer Ferdinand Magellan, is in 200 000 light years and is visible only since the southern hemisphere of the Earth.
N 81 is the 81st nebula cataloged in a study on the PNM driven by the astronomer Karl Henize in 1950, which afterward stole in the Space shuttle at time that astronaut. The presented image is a color representation of data obtained in September, 1997 with the camera WFPC2 of Hubble.

Image: The nebula N81, the small cloud of Magellan

 nebula N81, the small cloud of Magellan

Tarantula Nebula or NGC 2070


The Tarantula Nebula is a gigantic factory of manufacturing of stars. It is the biggest nebula of known emission.
Placed at a distance 170 000 light years, she can be observed in the constellation of the Sea bream in the southern sky.
It belongs to one of the nearby galaxies of the Milky Way, the Big Cloud of Magellan.
The Nebula of the Tarantula contains more than half a million times the mass of the Sun, this vast and blazing cloud welcomes some of the most massive known stars.
The nebula owes its name to the arrangement of its most brilliant sectors which look like in a sense the legs of a spider.
They extend since a central "body" where a heap of warm stars (conscript R136) illuminates and structures the nebula.
This name of one of the biggest spiders ground, was chosen because of the colossal proportions of the nebula indeed, it measures almost 1000 light years of wide and extends over more than a third of degree, is approximately the size of the full moon.


If it was situated in our own galaxy, at the distance of another stellar nursery, the Nebula of Orion (distant from only 1 350 light years), it would cover a quarter of the sky and would be visible even in broad daylight.
The astronomers realized this mosaic of four images to obtain a sight covering a square degree. Every individual image containing 64 million pixels, the resultant mosaic contains 256 million pixels.
The image is based on data collected through four filters, among which two which draw the hydrogen (in red) and the oxygen (in green). The ascendancy of the green in the image of the Tarantula results from the presence of the youngest and the warmest stars in this region.

Image: Nebula of the Tarantula ou NGC 2070
ESO: photo realized on December 21st, 2006

 Nebula of the Tarantula ou NGC 2070

Butterfly Nebula or NGC 2346


The butterfly nebula is situated in the approximately 2000 years light of the Earth in the direction of the constellation of the Unicorn.
It is the last moments of the spectacular system of binary stars that we see on the photo opposite in the center of the nebula.
These two stars are so close as they orbit the one around the other one in 16 days. Even with Hubble, the pair of stars cannot be seen as two separate constituents.
The astronomers think that one of the stars, by evolving developed to become a red giant and literally absorbed her companion.
Stars swirled together in spirals, and most of the external layers of the red giant were ejected in a dense disk which surrounds now the central star.
The nebula is also rich in clouds of dust, among which some form of long streak sink who point far from the central star.


The spatial telescope Hubble arrested this image of the nebula in shape "of wing of butterfly", NGC 2346.

Image: The Butterfly Nebula seen by the Hubble Space Telescope.

 Butterfly Nebula

Head of horse Nebula or Barnard 33


The Head of Horse nebula (officially known under the name of Barnard 33; IC434 is a dark nebula in the constellation of Orion.
The nebula is just below Alnitak (ζ Ori), the star most east of the belt of Orion. This nebula, situated in 1 350 light years was discovered for the first time in 1888 on a photographic plate taken in the look-out observatory of Harvard College.
It is easily recognizable by the shape at the head of horse which gave it its name. Indeed, behind the nebula is some hydrogen which, ionized by the brilliant star close Sigma Orionis, gives a red color.
The darkness of the head of horse is caused by the presence of a dense cloud of gas and dust.


This last one absorbs strongly the visible radiation emitted by the gas ionized by back plan (red on the photo). On the base of the head, we find young stars in the process of formation.

Image: The nebula of the head of horse

 Head of Horse nebula

Nebula Eta Carinae or NGC 3372


The Hull nebula is cataloged under the reference NGC 3372, it covers approximately three degrees of the sky at the distance of 8800 years light, what corresponds to a diameter of 460 years light.
It can be observed in the bare eye. It is the region HII We call regions HII, nebulas to emission constituted by clouds mainly consisted of hydrogen and with which most of the atoms are ionized, and sometimes extending over several light years. The ionization is produced by the nearness of one or several very warm stars, spectral type O or B, which shine strongly in the extreme ultraviolet ray, so ionizing the gas surrounding, from which these stars originally formed.  (region of ionized hydrogen) the most brilliant of the Milky Way. Its angular diameter exceeds 4° on photography.
The small said dark nebula of the " Hole of lock ( Keyhole) " (the cloud absorbing in the center of the nebula) juxtaposes on the most brilliant part of the nebula where the star a hour Carinae nests there.


The nebula of the Hull is a huge nebula situated in the Arm of the Sagittarius of our Galaxy. Although situated far from us, it is rather brilliant to be seen to the naked eye (but only since the southern hemisphere).

Image: The nebula NGC3372 Eta Carinae DSS image

 nebula NGC3372 Eta Carinae

Horseshoe Nebula or M17


M17 is a nebula in emission discovered by Cheseaux in 1746 then rediscovered by Messier in 1764 situated in the Sagittarius.
Also known under the names of nebula Omega, the Swan, the Horseshoe, or the Lobster, this very brilliant nebula, about the pinkish colors, is visible in the bare eye under the low latitudes (magnitude is similar 6). This is of for the fact that it shelters young stars arisen from the nebula and which irradiate the gas surrounding, so creating a region HII We call regions HII, nebulas to emission constituted by clouds mainly consisted of hydrogen and with which most of the atoms are ionized, and sometimes extending over several light years. The ionization is produced by the nearness of one or several very warm stars, spectral type O or B, which shine strongly in the extreme ultraviolet ray, so ionizing the gas surrounding, from which these stars originally formed. , a red color of the nebula is moreover that some ionized hydrogen.
In infrared, we were able to observe an important quantity of dusts, favorable to the formations of stars there.
Within the nebula would be an opened heap constituted by around thirty stars masked by the nebula.
The diameter of the nebula borders 40 light years.
The total mass of the gas which forms the nebula Omega is about 800 times that of the Sun. This gas extends over more than 40 light years.


M17 is situated in 5500 years light of our solar system. M16 and M17 would be in the same spiral arm of the Milky Way (the arm of the Sagittarius or Sagittarius-hull) and are maybe a part of the same complex giant of clouds of interstellar matter.

Image: The horseshoe nebula.

 horseshoe nebula

Nebula of pleiads or M45


Pleiads, or heap M45, are a heap opened by stars which observes in the north hemisphere, in the constellation of the Taurus.
The origin of the name "Pleiads" results from the Greek mythology: Pleiads are seven sisters, girls of Atlas and Pleione: Asterope, Merope (or Dryope, or Aero), Électre, Maïa, Taygete, Celaeno (or Selene) and Alcyone.
We count approximately 500 stars today composing this heap, a dozen of which is visible in the bare eye. It extends over 2 °, is the equivalent of 4 times the visible diameter of the Moon.
Its density is thus relatively weak with regard to the others heap opened. The age of the heap is estimated at 100 million years, but he should not live for a long time because he should part in 250 million years, partially because of his weak density.


Image: Nebula of pleiads

 Nebula of pleiads M45

Eagle Nebula or M16


The spatial telescope very often photographed the Eagle nebula.
Already the image acquired in 1995 showed very fine details inside its pillars of gas, real stellar crèches. By far, that looks like an eagle.
A more attentive examination of the Nebula of the Eagle, the watch than brilliant region is really a window in the center of a bigger dark shell of dust.
Through this window, a very floodlit studio appears there where a whole heap opened by stars is forming.
In this cavity, high pillars and the round globules of dark dust and cold molecular gas live there where stars continue to form.
Several young blue brilliant stars are already visible. Their light and their winds blow the remaining strands as well as the walls of gas and dust.
The nebula by emission of the Eagle, labeled M 26, is situated in approximately 6500 light years of the Earth, covers approximately 20 light years and is visible with binoculars in the direction of the constellation of the Snake.


Image: Nebula of the eagle or M16.
The image opposite combines three colors emitted specifically and was taken by the telescope of 0,9 m of Kitt Peak, in Arizona, in the USA.

 Nebula of the eagle or M16

Ring Nebula or Lyre Nebula or M57


Lyre nebula or M57 is among objects the most known for the catalog Messier. It was discovered in 1779 by Antoine Darquier de Pellepoix. It is an annular nebula which looks like the nebula Helix a lot. The real diameter of the ring is 1,3 al, is about a visible diameter 2 min of bow. The visible ring consists of oxygen and nitrogen ionized. The outside edge of the ring consists as for him of hydrogen. The dark part inside the ring is made by helium, and emits in the ultraviolet ray. M57 is often named Misty of the Ring, Nebula of the Lyre or simply The Lyre, the name that she pulls of her constellation host. A global nebula is a fine disk, in the irregular forms and in the luxurious colors. We so called up them, because seen in a small instrument, in the debuts of the observations, they appeared as weak planets. They appear as a nebula of small angular dimensions, often very symmetric circular shape and bounded well, by opposition at the diffuse nebulas which seem to dilute in the space and of irregular shape.
Numerous global nebulas have a shape of ring, as the ring of the Lyre, opposite. They show a density of matter stronger in suburb than inside.


A star is always in the center. At the end of life, when they exhausted their hydrogen, stars see their peripheral layers dilating and cooling, whereas the heart collapses and warms up to reach the melting point of the helium. Certain stars go as far as ejecting their peripheral layers creating an expanding cocoon. The heart put in nude is a star of type W or O which shines a lot of ultraviolet light and which incites the nebula.

Image: In this composite image, visible-light observations by NASA’s Hubble Space Telescope are combined with infrared data from the ground-based Large Binocular Telescope in Arizona to assemble a dramatic view of the well-known Ring Nebula. Credit: NASA, ESA, C.R. Robert O’Dell (Vanderbilt University), G.J. Ferland (University of Kentucky), W.J. Henney and M. Peimbert (National Autonomous University of Mexico) Credit for Large Binocular Telescope data: David Thompson (University of Arizona).

 Ring Nebula, Lyre Nebula planetary or M57

Nebula Dumbbell or M57


In 1764, the French astronomer Charles Messier described this magnificent cloud cosmic as an oval nebula without star.
Cataloged under the name of M 27, it is now known under the name of Nebula Dumbbell ("barbell" in English) because of its lengthened shape, what the eyes of Messier had noticed.
This deep image of brilliant misty global reveal the central star of Dumbbell and a network of stars of front and back plan in the pinkish constellation of the Fox (Vulpecula in Latin).
The dissimilar image adds up 8 hours of pose through a filter intended to record only the light resulting from atoms of hydrogen, drawing the structure of the weak outside halo of the nebula which extends over light years.
The Nebula Dumbbell, is a nebula similar to the fact that will happen our Sun when it will have exhausted its nuclear fuel.


The central star (at the origin of the nebula) has a visible magnitude of 13,5, what makes it with difficulty observable for an amateur astronomer. It is a dwarf white with very warm blue color (85 000K). It is accompanied with another stud, even weaker (magnitude 17).

Image: Dumbell planetary Nebula or M57

 Dumbell planetary Nebula or M57

Cone Nebula or NGC 2264


The Cone Nebula and the Christmas tree looks like a creature of nightmare, in a red sea, but in reality a mass of gas and dust located 2 500 light-years away in the constellation the Unicorn.
The nebula NGC 2264, a conical shape, is a finger of dark matter points to a group of stars. We see in this picture the visible part of a huge cloud of interstellar dense and opaque, composed of dust and hydrogen. This nebula has the distinction of being a variable brightness, due to the star that illuminates the cloud and which varies irregularly.
The red emission nebula surrounding the gas is due to ionized hydrogen gas surrounding the stars.
This monstrous pillar resides in a region of star formation.
This photo, taken by the camera of the Hubble Space Telescope, shows a cone of 2.5 light-years. The pillar has a full size of seven light-years.
Radiation from hot young stars (upper of the image), slowly eroding the top of the nebula.
Ultraviolet light heats the edges of the dark cloud, releasing gas in the region, relatively empty, the surrounding space.


Ultraviolet rays are shining hydrogen gas, which produces the red halo of light around the pillar and the arch that is seen near the low upper left side of the cone. This small arc, however, 65 times larger than our solar system.
The blue and white light of nearby stars is reflected by dust. Within these regions of dark dust, stars and planets in formation.
Over time, only the densest regions of the cone will resist erosion of the ultraviolet radiation of young massive stars. Astronomers believe that these pillars are incubators of stars.
The camera ACS made this observation, April 2, 2002. The color image is constructed from three separate images taken in blue, near infrared and hydrogen-alpha.

Image: Cone Nebula in the constellation of the Unicorn. Image taken by Hubble in April 2002.
NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M. Clampin (STScI), G. Hartig (STScI), the ACS Science Team and ESA.

 Cone Nebula in the constellation of the Unicorn or NGC 2264

Orion Nebula or M42 or NGC 1976


The Orion nebula presents to the telescope one of the most beautiful spectacles of the sky.
In the heart of the nebula, four blue stars, forming a trapeze, illuminate a great distance away the matter scattered in the space.
Atoms absorb the stellar light and re-emit it according to their appropriate colors, those some oxygen that is in the green, the hydrogen and the nitrogen in the red. The observations radio astronomical reveal us that the nebula of Orion is only a tiny part of the big opaque cloud of Orion.
Of the contraction of this cloud were born the stars of the Trapeze, as well as a group of primal stellar nebulas was situated behind the nebula of Orion.
The nebula of Orion was discovered in 1610 by Nicolas-Claude Fabri de Peiresc who was apparently the first one to notice his misty aspect although Ptolémée, Tycho Brahé and Johann Bayer identified the stars of his center as an only big star and Galilee had detected certain number of small stars when he observed this region with his astronomical telescope.


Image: The Orion nebula, so known under the name of M42 and NGC1976, is a nebula in broadcast / reflection of green color situated in the heart of the constellation of Orion.

 Orion nebula, so known under the name of M42

nebulas M42, M43 et NGC 1977


In the famous Orion Nebula M42, there is also the nebula NGC 1977 in blue on the image next to M42 in red, the color of hydrogen. In NGC 1977 there are also 2 small nebula NGC 1973 and NGC 1975 barely visible on the image.
The blue stars to the left of the image are in the nebula NGC 1981.
The small nebula M43 at the bottom left of M42 in red too. The big blue dot shining below the Great Red Spot, right of the image is the nebula NGC 1980
These nebulae are only a small part of the richness of interstellar objects in the region of Orion.
The Orion nebula is located at a distance of 1 500 light years from Earth.
The width of that heavenly view represents about 45 light years away


Image: This image shows a set of beautiful nebulae in the region of Orion, NGC 1976 or M42, M43 or NGC 1982, NGC 1977, NGC 1980, NGC 1973, NGC 1975, NGC 1981.
credit & Copyright: Tony Hallas

 nebulae in the region of Orion

North America Nebula or NGC 7000


The nebula NGC 7000 or the North America nebula is a nebula of enormous emission (3x2.3 degree. NGC 7000 is visible in the bare eye in the Milky Way, in 3 degrees east of Deneb in the constellation of the Swan. By a long photographic exposure, this nebula looks like the outline of the continent of North America, with a particularly good replica of the Gulf of Mexico.
Its red light is due to the gas of warmed hydrogen. Several other nebulas (IC 5070, IC 5068) are nearby of NGC 7000.
NGC 7000 is a chaotic complex within which get involved and become confused, dark veils of absorbent matter and vast stellar clouds were incited by an extremely warm blue star of the name of HD 199579.


Image: The nebula NGC 7000 reminds that of the American continent, where from its name.

 nebula NGC 7000

Lagoon Nebula or NGC 6523 or M8


Brilliant Misty of the Lagoon is a magnificent, easily visible object in the bare eye as a big foggy task situated at a distance considered in 5000 years light. M8 is a very big nebula with brilliant emission with an incorporated opened group.
This group of young stars warms the gas of the nebula, it causes a emission of light. Seen through binoculars the way sinks which divides the brilliant regions of the nebula, looks like a lagoon where from the name of this object.
With a small telescope we begin to perceive the complex folds of this nebula and the dark regions among more brilliant sectors. The dark parts of the nebula are the dense clouds of gas and dusts which are a nursery of stars.
To the naked eye, the light of the heap is dominated by a red global light which is provoked by the brilliant gaseous hydrogen, whereas dark strands result from the absorption by dense bands of dust.


The image opposite, taken by the telescope Curtis-Schmidt, show the nebula in emission in three precise colors emitted specifically by the hydrogen, the oxygen and the sulfur. The Nebula of the Lagoon is situated in approximately 5000 light years of the Earth in the constellation of the Sagittarius. The nebula covers a region furthermore with three times the diameter of the Full moon.

Image: The lagoon nebula or NGC 6523 or M8

 lagoon nebula or NGC 6523 or M8

Nebula NGC 1893 or IC 410


Magnificent rose of the heavens of the north hemisphere, the nebula by emission IC 410 or NGC 1893 is in about 12 000 light years of us in the constellation of the Coachman.
Brilliant cloud of hydrogen measures more than 100 light years of length.
It was sculptured by the stellar winds and the radiations emitted since the heap opened by stars NGC 1893 nested within it.
Formed in the interstellar cloud there is hardly 4 million years, the brilliant stud with the heap are visible just below the vast dark cloud of dust close to the center of the image.
Within 7 hours of this sight with big field detailed well, we notice two relatively dense currents of matter seeming to pass by central regions of the nebula. Possible places of formation of stars, these cosmic tadpoles measure about 10 light years of length.


Image: The nebula NGC 1893 or IC 410

 nebula NGC 1893 or IC 410

Trifide Nebula or M20


The Trifide nebula is brilliant misty circular one situated in the Sagittarius, rich in stars. It is at the same moment a nebula with emission and with reflection.
Bands of dark dusts seem to divide the nebula into three fragments, where from its name.
The nebula M20 appears as a big cloud of interstellar matter situated at a distance estimated at 5200 light years, in which the very warm stars draw a red anemone.
Visible in the bare and very easily locatable eye with a simple pair of binoculars.
The Trifide nebula was discovered by Guillaume Le Gentil in 1750.
The origin of the current name of M20 is attributed to John Herschel.
The objectors in the Anglicism can give to M20 the nickname of nebula of the Clover.
The Trifide nebula shares the star of this region extremely rich in the sky with numerous brilliant objects near, notably the nebula of the Lagoon situated near.
A triple system of stars occupies the center of the emissive region of the nebula, in the style of the Trapeze of the Orion nebula.


Image: The Trifide nebula or M20
Credit image: NASA, JPL-Caltech, J. Rho (SSC/Caltech)

This spectacular sight wrongly colored is taken by the Telescope Spatial Spitzer.
The astronomers used the infrared images Spitzer to consider embryonic stars hidden in the native dust of this schemer stellar crèche.
This image shows the nebula divided into three dark parts, darkening zones of dust which reveal strands of gas as well as births of brilliant stars.

 Trifide nebula

Helix Nebula or NGC 7293


The Helix nebula of the is a cosmic star often photographed by the amateur astronomers for its lively colors and its resemblance with a gigantic eye. The nebula discovered to 18th century, is situated in approximately 650 light years in the constellation of the Aquarius and belongs to a class of called objects misty global.
The global nebulas are the vestiges of stars which looked like in their past our Sun. When these stars die, they expel in the space their external gaseous layers.
These layers are warmed by the warm nucleus of the dead star, a white dwarf, and shine in the infrared and visible wavelengths.
Our Sun will undergo the same evolution when he will die in approximately five billion years. 
The infrared light of the external gaseous layers is represented in blue and in green.
The white dwarfish star is the tiny white point in the center of the photography.
The red color in the middle of the eye represents the last layers of gas blown during the death of the star.


The brilliant red circle situated in the center is the light of a disk of dust surrounding the white dwarfish star.
All the internal planets of the system were carbonized or vaporized whereas the volume of the dying star increased.

Image: The Helix nebula or NGC 7293 seen by the spatial telescope Spitzer

 Helix nebula or NGC 7293

Cat's Eye Nebula or NGC 6543


The Cat's Eye Nebula (NGC 6543 or of cat eye nebula) with a diameter of 20 seconds of bow, is situated in the north pole of the ecliptic, this very brilliant global nebula, is situated in the constellation of the Dragon.
This nebula possesses a very vast halo of matter, ejected during its phase of red giant. The halo measures 386 seconds of bow (5,8 minutes of bow).
According to a first interpretation, a binary system would be at the origin of the nebula.
The dynamic effects of two stars turning in orbit the one around the other one explain more easily the structure of this nebula, which seems much more complex than most of the other known global nebulas.
According to this model, the stellar wind of the central star created the envelope lengthened, made by dense and brilliant gas.
This structure is included inside two lobes of gas, ejected earlier by this star.
These lobes are marked by a ring of denser gas, probably ejected in the orbital plan of the companion of the central star.


Image: The Cat's Eye Nebula or NGC 6543 seen by the spatial telescope Hubble

 Cat's Eye Nebula or NGC 6543

Red square Nebula or MWC 922


Situated about 5000 light years in the Ophiucus constellation, still called Secretary bird, MWC 922 indeed shows a stunning symmetric structure in the form of square, when she is observed with the telescope of the Mountain Palomar and that of Keck.
The combination of both observations in infrared close (1,6 microns) shows in fact, under a certain angle, two conical cavities constituting a bipolar nebula produced by the ejection of matter from the superior layers of an unstable star.
The regularities, that we can observe associates in this biconic structure, are can be due to periodic waves propagating inside a disk of matter orbiting around the star, according to the astrophysicists.
How come that this nebula has a square shape?
The hypothesis which privileges the birth of the square nebula would want that the central stars expelled cones of gas. In the case of MWC 922 seen since the Earth, these cones would have practically been in right angle and seen each other by the side.
The researchers suppose that cones seen under another angle would appear under the same shape as the gigantic rings of supernovae 1987A.


Image: The Red square Nebula or MWC 922 seen by the telescope of the Mountain Palomar in California and the telescope Keck 2 of Mauna kea in the Hawaiian Islands

 Red square Nebula or MWC 922

Nebula NGC 3603


The huge nebula NGC 3603 accommodates within it, thousands of young glittering stars. This magnificent stellar panorama is one of the most massive heap of young stars of the Milky Way. NGC 3603 is an active nursery of formation of stars situated in the arm of the Hull of our Galaxy, in approximately 20 000 light years of our Solar system.
The image opposite of the telescope Hubble shows a heap of young stars surrounded by a vast region of dusts and gas.
The intense ultraviolet radiation and the solar winds of the most blue and the warmest stars inflated a big bubble around the heap.
The movement in the nebula of these winds of radiations formed big dark zones in the nebula.
These gaseous regions which extend over several light years, are directed to the center of the heap. We observe dark clouds in heap, called globules de Bok A globule of Bok is a dark heap of dusts and gas of the interstellar middle within which the birth of stars can begin. , visible in the right superior corner.
These clouds are constituted by dusts and by dense gases and are approximately 10 - 50 times as massive as the Sun.
A globule of Bok can undergo a gravitational collapse and lead to the formation of new stars. Most of the stars of this photo, are young very warm, visible stars in blue.


They emit ultraviolet radiations and violent winds which dig sorts of cavities in the gas and the dust which surround them The nebula NGC 3603 was discovered by John Herschel in 1834. The image covers approximately 17 light years and was realized on December 29th, 2005 with the instrument ACS (Advanced Camera for Surveys).

Image: A nursery activates of stars within the nebula NGC 3603 (shots of the spatial look-out observatory Hubble).

 nursery activates of stars within the nebula NGC 3603

Sharpless 171


Sharpless 171 is a nebula, of dusts and dense and cold gas, which accommodates within it, thousands of young glittering stars.
This region of formation of star in about 3000 light years of us is situated in the constellation of Cepheus. This region of formation of stars is 171eme of the catalog of nebulas in emission, created in 1959 by the astronomer Stewart Sharpless.
They are the warm stars of the heap of stars, Berkeley 59 which supply the energy which makes brilliant, the nebula Sharpless 171.



This heavenly landscape shows us the diffuse emission some atomic gas thanks to the use of a filter to narrow band and to a subtle coding of colors.

Image: credit & copyright: Antonio Fernandez

 Sharpless 171

Bubble Nebula or NGC 7635


NGC 7635, the Bubble Nebula, is inflated by the stellar wind of a massive central star of type O, the star BD 602,522.
A giant molecular cloud is visible on the right of the image. This cloud contains the expansion of the gas bubble, then it is rejected by radiation from the hot central star of the bubble.
The radiation heats the dense regions of molecular cloud and causes it to enlightenment.
The Bubble Nebula is about 10 light years in diameter and is visible in the constellation Cassiopeia.
The Bubble Nebula is also known as NGC 7635.
Estimated its distance at about 11 000 light years.


Image: The Bubble Nebula or NGC 7635.
Credit & Copyright: Russell Croman

 The Bubble Nebula or NGC 7635

Crab Nebula or M1 or NGC 1952


The Crab Nebula or M1 is the typical result of a starburst or visible residue of the explosion of a supernova. This supernova exploded in 1054, observed by several astronomers of the Far East from July 1054 to April 1056.
These mysterious filaments, are not only extremely complex, but seem to have less mass than the original supernova and higher speed than expected. It is situated at a distance of about 2 kiloparsecs is 6300 light years from Earth in the constellation Taurus. The nebula has a diameter of 11 light years and its expansion velocity is 1500 km / s. This is the first astronomical object that has been identified with a supernova explosion. In the center of the nebula is a pulsar, that is to say, a neutron star as massive as the Sun but with only the size of a small town.
The Crab Pulsar rotates on itself at a speed of 30 times per second. It radiates about 200,000 times more energy than the Sun and this in an extremely wide frequency range. A supernova is the visible phenomenon, directly from the cataclysmic explosion of a star that leads to its total destruction and therefore the death of the star. This explosion is accompanied by a gigantic increase its brightness as seen from Earth, which can last several weeks and even months.


It is visible in daylight and at night it can be as bright as the moon and even give a shadow objects.
A supernova is therefore often as a new star, whence its name, nova. Supernovae are rare events in our Milky Way, about one to three per century, by cons across the Universe, we observe every day.
It was during the supernova explosion the star releases its chemical elements synthesized during its existence and after the explosion itself.
The shockwave from the supernova favors the formation of new stars accelerating contraction of regions of gas and dust in the interstellar medium.
The novae, unlike supernovae are thermonuclear explosions from causing a partial destruction of the star by expelling a portion of its surface into interstellar space.

Image: The Crab Nebula or M1 is the typical result from a star explosion. The death of a star can be mild or severe, depending on its mass.
Picture taken by the Hubble Space Telescope.

 Crab Nebula or M1 or NGC 1952

Thor's Helmet Nebula or NGC 2359


This emission nebula in the form of winged helmet suggestive is commonly called The Helmet of Thor. The diameter of a helmet suitable Norse god, is 30 light years. In fact, the helmet is a bubble of interstellar matter, blown by wind energy from the central star is extremely hot, massive and bright, created in the surrounding molecular cloud.
Identified as a Wolf-Rayet star, the central star is a giant star extremely hot.
The stars of Wolf-Rayet stars are rare blue giants which develop stellar winds traveling millions of miles per hour.
Interaction with a large molecular cloud close to contribute to complex shapes and structures of curved arches shock of this nebula.
We think she is going through a very brief phase of its evolution prior to its supernova explosion.


Cataloged under number NGC 2359, the nebula is located 15 000 light years away in the constellation Canis Major.
This sharp image shows remarkable detail structures in the filaments of the nebula. It also sees the colors of emerald due to emission of oxygen atoms around the luminescent gas.

Image:  The emission nebula visible here, is known by the name of Thor's Helmet or NGC 2359 in the constellation Canis Major.
Credit and Copyright: Star Shadows Remote Observatory & PROMPT / UNC (Steve Mazlin, Jack Harvey, Rick Gilbert, and Daniel Verschatse)

 Thor's Helmet Nebula or NGC 2359

Wizard Nebula, or NGC 7380


The image of the wizard nebula (see opposite), published on the popular portal for astronomy APOD (Astronomy Picture Of the Day), was taken by amateur astronomer and photographer Rolf Geissinger.
The splendor of the sky is lit by the stars in it and the nearby stars located behind them.
Sufficiently strong gravitation of the nebula NGC 7380, triggering the birth of stars at its heart.
Stellar winds and radiation of the stars are so powerful that the gas and dust are pushed and create shining on cliffs. Witch of the nebula is located just 8 000 light years, it surrounds the open cluster NGC 7380.
The shape of these cliffs cosmic dust between the stars, can evoke the silhouette of a sorcerer medieval, although we could not see the hooded robe, nor the wide belt.
However, this region of star formation extends some 100 light years, which land in the sky gives an apparent size slightly larger than the Moon.


Wizard nebula can contemplate with a small telescope, for that you need to point toward the constellation of Cepheus, the King of Ethiopia.

Image: The red color comes from the fire of new stars located in the heart of the nebula NGC 7380 and the Sorcerer.
Red is the signature characteristic of ionized atoms of hydrogen.
Image Credit & Copyright: Rolf Geissinger

 Wizard Nebula, or NGC 7380

Nebula NGC 2818


The planetary nebula NGC 2818 is nested inside the open cluster NGC 2818A Star and has a visual magnitude of 8.2 and therefore invisible to the naked eye. The cluster and nebula are more than 10,000 light-years away in the southern constellation Pyxis called Compass. The colors seen from the various components more or less ionized in which each emit a wavelength-kind. The colors in this image represent a range of emissions from clouds of the nebula.
Red represents nitrogen, green represents hydrogen, and blue, oxygen. The name "planetary nebula" comes from the first observations of these objects, which sometimes have a circular appearance, like a planet.


In reality it is star reached the end of life, violently expelled in the form of gas, much of the material they are made. The planetary nebula NGC2818 is detached from the surrounding stars. This Hubble image was taken in November 2008 with the WFPC2 instrument (Wide Field Planetary Camera 2).

Image: Source press release Hubble & Gilbert Javaux - PGJ Astronomy Illustration: NASA, ESA, et the Hubble Heritage Team (STScI/AURA)

 Planetary Nebula NGC 2818

Eskimo Nebula or NGC 2392


The planetary nebula NGC 2392 or the Eskimo, was discovered in 1787 by astronomer William Herschel in the constellation Gemini.
NGC 2392 looks like a head surrounded by a parka. This nebula consists of two discs, the inner disk bright enough and the outer disc ring-shaped irregular.
NGC 2392 is at a distance of approximately 4000 years light.
There are only 10 000 years, gas visible on the image below against constituted the outer layers of a sun-like star. The central star is clearly visible in this image.
The internal filaments visible in white were ejected by strong wind of particles from the central star.
The outer disk contains filaments of orange color, a light-year long.


Image: taken by the Hubble Space Telescope in January 2000. One can observe its concentric rings that justifies its name of Eskimo Nebula. His modest apparent magnitude (9.90) can not see with the naked eye, but can be seen with small telescopes. Credit: NASA

 Eskimo Nebula or NGC 2392

Planetary Nebula NGC 6751


Planetary nebulae are simple spheres shaped planet when viewed through a small telescope. But the Hubble Space Telescope is able to show us the details of his celestial objects.
Planetary nebulae have spherical shapes varied, are fluorescent balls of gas expelled by a central star at the end of life.
This Hubble image is a composite colored example of a planetary nebula, but with complex characteristics. This image of NGC 6751 was selected in April 2000 to commemorate the tenth anniversary of Hubble in orbit. The colors were chosen to represent the relative temperatures of gas (blue, orange and red, the hottest gas gas coldest).
These are the winds of intense heat and radiation from the central star that create the characteristic shape of the nebulae.
The central star dying, shines as Suns 9000. It expels its outer gaseous layers and exposes its core burning whose strong ultraviolet radiation illuminates the ejected gas.


The diameter of the nebula is about 0.85 light-years, or about 600 times the size of our solar system. NGC 6751 is 6500 light-years from us in the constellation of the Eagle.

nota: NGC (New General Catalog) is one of the best known catalogs in the field of amateur astronomy with the Messier catalog.

Image: The gas cloud of the planetary nebula NGC 6751 looks like a celestial eye. The dying star at the center and winds eject dust from outer gaseous layers of the star.
Credit: Hubble Heritage Team (STScI/ AURA), NASA

 Planetary Nebula NGC 6751

Boomerang nebula


The Boomerang Nebula is a young planetary nebula located in the constellation Centaurus 5000 light years from the solar system. The central star but still light at the end of life, expels its shell of gas and dust in the cold space. These gases form a cloud of material which extends around the star like butterfly wings. This nebula is officially known to be the coldest object in the Universe. Indeed, the global temperature has been measured at 1 ° Kelvin (1 degree above absolute zero, which is even colder than the temperature of deep space, diluted and cooled by the expansion of the Universe, it has a temperature of 2,728 K (-270.424 ° C). This information was revealed in 1995 by two astronomers Sahai and Nyman who observed the nebula with submillimeter telescope 15 meters located in Chile. Form diffuse node butterfly makes it very different from other planetary nebulae usually resemble colorful diffuse disc or bubbles blown by a dying central star. However, the Boomerang Nebula is so young that she did not have time to develop this round structure.


The general shape of butterfly wings appear to have been created by an excessively strong wind blew the gas far from the central star. It is this rapid expansion of the nebula that cools the gas to reach this incredible temperature of 1 ° K. The blue color of the image is from light reflected by the star dust particles plant.

Image: The image taken from the Hubble telescope in 1998, reveals the surprising details of the nebula Boomerang. These are the two astronomers Keith Taylor and Mike Scarrott who in 1980 called this nebula, nebula boomerang after observing from Australia. Credit public domain: NASA / ESA.

 Boomerang nebula

See also

1997-2013 © - Astronomy, Astrophysics, Evolution and Earth science.
Reproduction prohibited without permission of the author.
galaxy NGC1672
Are we alone
in the universe?
Merope nebula IC 349 and stellar winds
Stellar winds of the Merope nebula...
Particles to the
biochemical life...
Composition of interstellar dust
Composition of
interstellar dust...
Electron, a kind of
electrical point...
Asteroid the threat
for the life...
Aristotle's geocentric world
Egocentric vision,
the man at the center...
million al
From the largest to
the smallest distance...
Entropy, the increase
of the disorder...
geologic time
Geological time
on our planet...
Sputnik, the Russian companion...
Interstellar dust
is found everywhere...
The Earth-Crossing Asteroids - NEO
Earth-Crossing Asteroids...
inanimate and living
Border between
inanimate and living...
The oldest image of the Earth
The oldest image
of the Earth...
mass of the proton
E=mc2 explains
the mass of the proton...
séquence de hubble
Sequence of Hubble
and types of galaxies...
gravity according to Einstein
Image of gravity
from Albert Einstein...
gravitational lenses
Illusions created by
gravitational lenses...
forêt lyman
Does the black mater exist?
protubérances solaires et spicules
Spicules of blue Sun...
Hadron is not
a fixed object...
nebula NGC 2170 seen by VISTA
Nebula NGC 2170
seen by VISTA...
Rosette nebula or ngc2237
sculpture designed by the Rosetta...