The Helix Nebula: Unraveling at the Seams

Spitzer_sig12-011_1024

spitzer_sig12-011 October 3rd, 2012

Credit: NASA/JPL-Caltech

A dying star is throwing a cosmic tantrum in this combined image from NASA's Spitzer Space Telescope and the Galaxy Evolution Explorer (GALEX), which NASA has lent to the California Institute of Technology in Pasadena. In death, the star's dusty outer layers are unraveling into space, glowing from the intense ultraviolet radiation being pumped out by the hot stellar core.

This object, called the Helix nebula, lies 650 light-years away, in the constellation of Aquarius. Also known by the catalog number NGC 7293, it is a typical example of a class of objects called planetary nebulae. Discovered in the 18th century, these cosmic works of art were erroneously named for their resemblance to gas-giant planets.

Planetary nebulae are actually the remains of stars that once looked a lot like our sun. These stars spend most of their lives turning hydrogen into helium in massive runaway nuclear fusion reactions in their cores. In fact, this process of fusion provides all the light and heat that we get from our sun. Our sun will blossom into a planetary nebula when it dies in about five billion years.

When the hydrogen fuel for the fusion reaction runs out, the star turns to helium for a fuel source, burning it into an even heavier mix of carbon, nitrogen and oxygen. Eventually, the helium will also be exhausted, and the star dies, puffing off its outer gaseous layers and leaving behind the tiny, hot, dense core, called a white dwarf. The white dwarf is about the size of Earth, but has a mass very close to that of the original star; in fact, a teaspoon of a white dwarf would weigh as much as a few elephants!

The glow from planetary nebulae is particularly intriguing as it appears surprisingly similar across a broad swath of the spectrum, from ultraviolet to infrared. The Helix remains recognizable at any of these wavelengths, but the combination shown here highlights some subtle differences.

The intense ultraviolet radiation from the white dwarf heats up the expelled layers of gas, which shine brightly in the infrared. GALEX has picked out the ultraviolet light pouring out of this system, shown throughout the nebula in blue, while Spitzer has snagged the detailed infrared signature of the dust and gas in yellow A portion of the extended field beyond the nebula, which was not observed by Spitzer, is from NASA's all-sky Wide-field Infrared Survey Explorer (WISE). The white dwarf star itself is a tiny white pinprick right at the center of the nebula.

The brighter purple circle in the very center is the combined ultraviolet and infrared glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust was most likely kicked up by comets that survived the death of their star.

Before the star died, its comets, and possibly planets, would have orbited the star in an orderly fashion. When the star ran out of hydrogen to burn, and blew off its outer layers, the icy bodies and outer planets would have been tossed about and into each other, kicking up an ongoing cosmic dust storm. Any inner planets in the system would have burned up or been swallowed as their dying star expanded.

Infrared data from Spitzer for the central nebula is rendered in green (wavelengths of 3.6 to 4.5 microns) and red (8 to 24 microns), with WISE data covering the outer areas in green (3.4 to 4.5 microns) and red (12 to 22 microns). Ultraviolet data from GALEX appears as blue (0.15 to 2.3 microns).

Provider: Spitzer Space Telescope

Image Source: http://www.spitzer.caltech.edu/images/5259-sig12-011-The-Helix-Nebula-Unraveling-at-the-Seams

Curator: Spitzer Space Telescope, Pasadena, CA, USA

Image Use Policy: http://www.spitzer.caltech.edu/info/18-Image-Use-Policy

Image Details

Image Type
Observation
Object Name
Helix Nebula NGC 7293
Subject - Milky Way
Nebula > Type > Planetary

Distance

Universescale1
650 light years
Spitzer_sig12-011_128
 

Position Details

Position (ICRS)
RA = 22h 29m 38.6s
DEC = -20° 50’ 20.1”
Orientation
North is up
Field of View
50.2 x 50.2 arcminutes
Constellation
Aquarius

Color Mapping

  Telescope Spectral Band Wavelength
Blue GALEX (FUV) Ultraviolet (Far-UV) 150.0 nm
Blue GALEX (NUV) Ultraviolet (Near-UV) 230.0 nm
Green Spitzer (IRAC) Infrared (Near-IR) 3.6 µm
Green Spitzer (IRAC) Infrared (Near-IR) 4.5 µm
Red Spitzer (IRAC) Infrared (Mid-IR) 8.0 µm
Red Spitzer (MIPS) Infrared (Mid-IR) 24.0 µm
Spectrum_ir1
Blue
Blue
Green
Green
Red
Red
Spitzer_sig12-011_1280
×
ID
sig12-011
Subject Category
B.4.1.3  
Subject Name
Helix Nebula, NGC 7293
Credits
NASA/JPL-Caltech
Release Date
2012-10-03
Lightyears
650
Redshift
650
Reference Url
http://www.spitzer.caltech.edu/images/5259-sig12-011-The-Helix-Nebula-Unraveling-at-the-Seams
Type
Observation
Image Quality
Good
Distance Notes
Facility
GALEX, GALEX, Spitzer, Spitzer, Spitzer, Spitzer
Instrument
FUV, NUV, IRAC, IRAC, IRAC, MIPS
Color Assignment
Blue, Blue, Green, Green, Red, Red
Band
Ultraviolet, Ultraviolet, Infrared, Infrared, Infrared, Infrared
Bandpass
Far-UV, Near-UV, Near-IR, Near-IR, Mid-IR, Mid-IR
Central Wavelength
150, 230, 3600, 4500, 8000, 24000
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
ICRS
Equinox
J2000
Reference Value
337.4107025, -20.8389282
Reference Dimension
6019.0, 6019.0
Reference Pixel
3010.5, 3010.5
Scale
-0.000138877, 0.00013887749
Rotation
0.04
Coordinate System Projection:
TAN
Quality
Full
FITS Header
Notes
Creator (Curator)
Spitzer Space Telescope
URL
http://www.spitzer.caltech.edu
Name
Email
Telephone
Address
1200 E. California Blvd.
City
Pasadena
State/Province
CA
Postal Code
91125
Country
USA
Rights
http://www.spitzer.caltech.edu/info/18-Image-Use-Policy
Publisher
Spitzer Science Center
Publisher ID
spitzer
Resource ID
sig12-011.tif
Metadata Date
2012-10-03
Metadata Version
1.1
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Detailed color mapping information coming soon...

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Universescalefull
650 light years

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