nov 142013

November 14, 2013

The North America Nebula, an emission nebula in Cygnus

NGC 7000

Image Credit & Copyright: J-P Metsävainio 

The North America Nebula (NGC 7000) is an emission nebula of some 130 light-years across with a shape that resembles the continent of North America, complete with a prominent Gulf of Mexico. It is located roughly 1,600 light-years away from Earth in the Orion Arm of our Galaxy, in the northern constellation of Cygnus (the Swan), close to the bright star Deneb.

The North America Nebula and the nearby Pelican Nebula, (IC 5070) are in fact parts of the same star-forming (H II) region, separated by a broad band of interstellar dust that absorbs the light of stars behind it. Actually, the obscuring dust doesn’t lie between the two nebulae, but lies between the Earth and the nebula complex, and thereby determines the shape as we see it.

Throughout the North America Nebula are clusters of young stars (about one million years old) while slightly older but still very young stars (about 3-5 million years) are also liberally scattered across the complex. Some areas of this nebula are still very thick with dust and are likely to be the youngest stars in the complex (less than a million years old).

Cygnus’s Wall, seen in this image, is a term for the “Mexico and Central America part” of the North America Nebula, which is the most active region of star formation in the nebula. These enormous columns of gas and dust – dense enough to collapse to form stars – span about 15 light-years, and are lit and eroded by bright young stars.

The distance of the nebula complex is not precisely known, nor is the star responsible for ionizing the hydrogen so that it emits light. Recently, the 2MASS infrared telescope has shown that there is a massive O-type star in the general area of the nebulae, which is the most likely source of their radiation. However, some other sources say that is probably Deneb.

The North America Nebula is covering an area of more than four times the size of the full moon; but its surface brightness is low, so normally it cannot be seen with the unaided eye. However, the nebula can be seen with binoculars from a dark location

This image shows a swirling landscape of dust and young stars in the southern part of the North America Nebula and is taken in the HST-palette from the emission of ionized elements, Red=Sulfur, Green=Hydrogen and Blue=Oxygen. Total exposure time approximately 120 hours.

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