Aug 12, 2011 11:49 GMT  ·  By
The Necklace Nebula is located 15,000 light-years away in the constellation Sagitta
   The Necklace Nebula is located 15,000 light-years away in the constellation Sagitta

Astronomers operating the NASA/ESA Hubble Space Telescope have just released a new image of a cosmic structure called PN G054.2-03.4, but which is known among experts at the Necklace Nebula.

The photos shows the object in all of its glory. It appears to be extremely bright, which enables astronomers to peer deeper within it than ever before. According to scientists, this structure is in fact a planetary nebula.

This class of objects is different from regular nebulae through the fact that they appear to be very fluffy when viewed from a distance. Centuries ago, when telescopes were a lot smaller than they are today, astronomers such as Charles Messier mistook them for gas giants.

In fact, it's only their appearance that separates them from conventional nebulae. They are the remnants of Sun-sized stars, which moved past their red giant phase, and shed the outer layers of their engorged atmospheres. The core of such nebulae is generally powered by a white dwarf.

This is the last stage in the life of a Sun-like star. Such an object usually contains extremely limited amounts of hydrogen, having consumed the gas through nuclear fusion over the course of its main sequence. As such, all thermonuclear reactions in and on the white dwarf have stopped.

Instead of hydrogen, the star switches to burning helium, which provides it with an additional 3 billion years of life. The nebula around it is made up of the atmospheric layers it shed while bloated as a red giant. When the Sun will enter this phase, it will grow past Earth's orbit, destroying the planet.

The thing that makes the Necklace Nebula look so interesting is the fact that it has extremely dense and bright gas knots strung in a configuration that makes astronomers think of a necklace. The cosmic object is around 12 trillion miles wide.

Another amazing aspect of this particular nebula is the fact that it is being produced by a binary system, rather than a single star. The smaller one orbits inside the atmosphere of its larger companion, at a distance of only a few million miles.

The two are so close together that they complete a full rotation in around a day. The vast centrifugal forces produced by this gravitational interaction is making the large star lose vast amounts of its hydrogen gas through an area strung along its Equator.

The gas knots visible in the new Hubble image are arranged in this pattern because they were produced by this equatorial region. This binary system lies around 15,000 light-years away, in the constellation Sagitta.

The new composite image Hubble collected with its Wide Field Camera 3 (WFC3) was taken on July 2. It shows hydrogen in blue, oxygen in green and nitrogen in red. The telescope is managed by the NASA Goddard Space Flight Center (GSFC), in Greenbelt, Maryland.