Eagle Nebula
The Eagle Nebula, or IC 4703 (see Index Catalogue ) is a mist in conjunction with an open star clusters. The open cluster Messier catalog carries in the name of M 16 and NGC in the NGC number 6611th In many catalogs nebulae and star clusters are listed synonymous, so that the Messier catalog designation is usually used for the fog. It is located in the constellation of the Serpent at the coordinates 18h19m ( right ascension ) and -13 ° 47 ' ( declination ).
Description
The Eagle Nebula is from the Sun about 7,000 light-years. It has an apparent magnitude of 6.4 m.
The Eagle Nebula is an emission nebula (type H II ) from which forms an open cluster. It consists primarily of hydrogen, which could join together due to the low temperature hydrogen molecules. The approximately 20 light-years wide nebula contains dust pillars, which are up to 9.5 light- years long and at the tip of which new stars are, why they were baptized Pillars of Creation ( Pillars of Creation ). The opacity of the fog comes about through silicate and carbon particles. The mean age of the stars is about 800,000 years. Some stars are very young, the age of the youngest stars is estimated to 50,000 years.
Discovery
Was discovered in the open cluster of the Swiss astronomer Jean -Philippe de Chéseaux during the mapping of 21 nebulae in the years 1745 and 1746. The Eagle Nebula is number 4 in its list and was probably observed already in 1745. In a letter to his father, which includes its list of 21 nebulae, he described the fog as follows:
" A star cluster between the constellations Ophiuchus, Sagittarius and Antinous, whose right ascension 271 ° 3 ' 10" and Southern declination 13 ° 47' 20 ". "
Regardless of the observations Chésauxs because his list was not published until 1892, the French astronomer Charles Messier observed about 18 years later, the same fog. He wore his observation on June 3, 1764 in his Messier catalog. The observed star clusters is described in his catalog as " a bunch of small stars, embedded in a faint glow ". He also noted that this cluster " like a mist appears smaller telescope" into one. A direct observation of the nebula, as the recordings by the Hubble Space Telescope show it is not occurred to here. Messier described the fog probably as " embedded in a faint glow " because the former telescopes did not have sufficient contrast performance. Only much later unique observations of the nebula were carried out and made towards the beginning of the 20th century, first shots.
Research
In 1995, the Hubble Space Telescope images of the region, which fascinating structures disclosed. For the first time get a detailed insight into the formation processes of stars that have never been observed from this angle before. These columns are similar in structure to a bird of prey swooping, therefore the fog got its name.
In early 2007 made the Spitzer telescope images in the infrared range. These images showed the intact fog as we know it from the well-known images of the Hubble Space Telescope and a cloud of hot dust. It is believed that this cloud are remains of a stellar explosion, or supernova, and that this cloud has probably enough force to alter the molecular clouds that make up the popular pillars of creation in its form. Thus the possibility exists that the cloud of the supernova tears the dust and gases out of the fog with it and it and hidden behind young star exposes. The associated supernova, which is regarded as a trigger for this event, could probably be observed one to two thousand years ago in the sky. Due to the distance of seven thousand light years, the event has eight or nine thousand years is so in the past. Astronomers speculate that the columns could already be blown away, we however, due to the great distance and the time required for the light for this trip (see speed of light), nor can see the state of the nebula seven thousand years ago.
Image of a section of the Eagle Nebula by the Hubble Space Telescope (false color representation): The Pillars of Creation.
Hubble image of 2006