NASA Zooms in on the Pillars of Creation –“Toppled By a Supernova Explosion”

A new, striking image from NASA’s Chandra X-ray Observatory and Hubble Space Telescope shows the intact dust towers of the spectacular star-forming region known as the Pillars of Creation, which is located in the southern portion of the Eagle Nebula, next to a giant cloud of hot dust thought to have been scorched by the blast of a star that exploded, or went supernova. Astronomers speculate that the supernova’s shock wave could have already reached the dusty towers, causing them to topple about 6,000 years ago. However, because light from this region takes 7,000 years to reach Earth, we won’t be able to capture photos of the destruction for another millennium or so.

Astronomers have long predicted that a supernova blast wave would mean the end for the popular pillars. The region is littered with 20 or so stars ripe for exploding, so it was only a matter of time, they reasoned, before one would blow up. Spitzer Space Telescope infrared observations in 2007 suggested that one of these stellar time bombs has in fact already detonated, an event humans most likely witnessed 1,000 to 2,000 years ago as an unusually bright star in the sky.

 

Above the pillars is the enormous cloud of hot dust, which astronomers think was seared by the blast wave of a supernova explosion. Evidence for this scenario comes from similarities observed between this hot dust and dust around known supernova remnants. The dust also appears to have a shell-like shape, implying that a supernova blast wave is traveling outward and sculpting it.

The mysterious dust was first revealed in previous images from the European Space Agency’s Infrared Space Observatory, but Spitzer’s longer-wavelength infrared instrument was able to tentatively match the dust to a supernova event. “Something else besides starlight is heating this dust,” said Dr. Alberto Noriega-Crespo, at the Spitzer Science Center.

The new composite image above shows the region around the Pillars, which are about 5,700 light years from Earth. The image combines X-ray data from NASA’s Chandra X-ray Observatory and Hubble Space Telescope optical data. The optical image, taken with filters to emphasize the interstellar gas and dust, shows dusty brown nebula immersed in a blue-green haze, and a few stars that appear as pink dots in the image. The Chandra data reveal X-rays from hot outer atmospheres from stars. In this image, low, medium, and high-energy X-rays detected by Chandra have been colored red, green, and blue.

Using Chandra, researchers detected over 1,700 individual sources of X-rays in the Eagle Nebula (only a fraction are seen in this small field of view). Optical and infrared identifications with stars were used to sort out chance interlopers in the foreground or background, and to determine that more than two-thirds of the sources are likely young stars that are members of the NGC 6611 cluster.

Chandra’s unique ability to resolve and locate X-ray sources made it possible to identify hundreds of very young stars, and those still in the process of forming (known as “protostars”). Infrared observations from NASA’s Spitzer Space Telescope and the European Southern Observatory indicate that 219 of the X-ray sources in the Eagle Nebula are young stars surrounded by disks of dust and gas and 964 are young stars without these disks.

Combined with the Chandra observations, the data show that X-ray activity in young stars with disks is, on average, a few times less intense that in young stars without disks. This behavior is likely due to the interaction of the disk with the magnetic field of the host star. Much of the matter in the disks around these protostars will eventually be blown away by radiation from their host stars, but, in certain cases, some of it may form into planets.

In the image, some of the X-ray sources appear to be located in the Pillars.

However, an analysis of the absorption of X-rays from these sources indicates that almost all of these sources belong to the larger Eagle Nebula rather than being immersed in the Pillars.

Three X-ray sources appear to lie near the tip of the largest Pillar. Infrared observations show a protostar containing four or five times the mass of the Sun is located near one of these sources – the blue one near the tip of the Pillar. This source exhibits strong absorption of low-energy X-rays, consistent with a location inside the Pillar. Similar arguments show that one of these sources is associated with a disk-less star outside the Pillar, and one is a foreground object.

The Daily Galaxy via NASA

Image credit: NASA/CXC/INAF/M.Guarcello et al.; Optical: NASA/STScI

 

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