ESO: The Helix in New Colours (NGC 7293)

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ESO: The Helix in New Colours (NGC 7293)

Post by bystander » Thu Jan 19, 2012 3:18 pm

The Helix in New Colours (NGC 7293)
European Southern Observatory | VISTA | 2012 Jan 19
ESO’s VISTA telescope, at the Paranal Observatory in Chile, has captured a striking new image of the Helix Nebula. This picture, taken in infrared light, reveals strands of cold nebular gas that are invisible in images taken in visible light, as well as bringing to light a rich background of stars and galaxies.

The Helix Nebula is one of the closest and most remarkable examples of a planetary nebula*. It lies in the constellation of Aquarius (The Water Bearer), about 700 light-years away from Earth. This strange object formed when a star like the Sun was in the final stages of its life. Unable to hold onto its outer layers, the star slowly shed shells of gas that became the nebula. It is evolving to become a white dwarf star and appears as the tiny blue dot seen at the centre of the image.

The nebula itself is a complex object composed of dust, ionised material as well as molecular gas, arrayed in a beautiful and intricate flower-like pattern and glowing in the fierce glare of ultraviolet light from the central hot star.

The main ring of the Helix is about two light-years across, roughly half the distance between the Sun and the nearest star. However, material from the nebula spreads out from the star to at least four light-years. This is particularly clear in this infrared view since red molecular gas can be seen across much of the image.

While hard to see visually, the glow from the thinly spread gas is easily captured by VISTA’s special detectors, which are very sensitive to infrared light. The 4.1-metre telescope is also able to detect an impressive array of background stars and galaxies.

The powerful vision of ESO’s VISTA telescope also reveals fine structure in the nebula’s rings. The infrared light picks out how the cooler, molecular gas is organised. The material clumps into filaments that radiate out from the centre and the whole view resembles a celestial firework display.

Even though they look tiny, these strands of molecular hydrogen, known as cometary knots, are about the size of our Solar System. The molecules in them are able to survive the high-energy radiation that emanates from the dying star precisely because they clump into these knots, which in turn are shielded by dust and molecular gas. It is currently unclear how the cometary knots may have originated.
  • Planetary nebulae have nothing to do with planets. This confusing name arose because many of them show small bright discs when observed visually and resemble the outer planets in the Solar System, such as Uranus and Neptune. The Helix Nebula, which also bears the catalogue number NGC 7293, is unusual as it appears very large, but also very faint, when viewed through a small telescope.
  • ESO's Visible and Infrared Survey Telescope for Astronomy (VISTA) has captured this unusual view of the Helix Nebula (NGC 7293), a planetary nebula located 700 light-years away. The coloured picture was created from images taken through Y, J and K infrared filters. While bringing to light a rich background of stars and galaxies, the telescope's infrared vision also reveals strands of cold nebular gas that are mostly obscured in visible images of the Helix.

ScienceShot: A Revealing Look at the Helix Nebula
Science NOW | Sid Perkins | 2012 Jan 19
A new infrared image of the Helix Nebula in the constellation Aquarius is shedding light on the enigmatic object's structure. Captured by the 4.1-meter VISTA telescope in northern Chile, the image, released online today by the European Southern Observatory, reveals solar-system-sized clumps and strands of hydrogen gas. These features, dubbed cometary knots because they typically point directly away from the star at the center of the nebula, can't be easily seen in visible light (inset). The main ring of the Helix Nebula is about 2 light-years across, about half the distance from our sun to the nearest star. The faint red halo that can be seen across much of the infrared image spans several light-years, the researchers estimate. Material in the nebula, which lies about 700 light-years from Earth, was shed from a sun-type star (blue dot denoted with arrow) during the final stages of its life. Eventually that star, which now shines fiercely in ultraviolet wavelengths, will evolve to become a white dwarf, a dense star about as massive as our sun yet only slightly larger than Earth.

The Helix screams in infrared
Discover Blogs | Bad Astronomy | 2012 Jan 19
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Re: ESO: The Helix in New Colours (NGC 7293)

Post by Beyond » Thu Jan 19, 2012 9:39 pm

Hmm... There does seem to be a great resembalence, except for the black hole in the middle of the third eye. :mrgreen:
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Re: ESO: The Helix in New Colours (NGC 7293)

Post by neufer » Thu Jan 19, 2012 9:50 pm

Beyond wrote:
Hmm... There does seem to be a great resembalence,
except for the black hole in the middle of the third eye. :mrgreen:
[list]Supernova Type III[/list]
Art Neuendorffer

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Re: ESO: The Helix in New Colours (NGC 7293)

Post by Beyond » Thu Jan 19, 2012 10:33 pm

Super Nova Type III :?: Oh, that's the newly realized type super nova in which most of the explosion is going away from us, so we only see a little that comes this way, which makes the center look dark. Catching a typeIII is really hard to do. After a while, a little of what we can see, wraps around a bit and obscures the dark center, thus making it impossible to tell that it's a type III.
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