Echoes of a Death Cry

Wise_wise2012-002_500

WISE_WISE2012-002 March 15th, 2012

Credit: NASA/JPL-Caltech/UCLA

Over 11,000 years ago, a massive, supergiant star in our Galaxy came to the end of its life. The stars core collapsed to form an incredibly dense ball of neutrons, and its exterior was blasted away in an immense explosion astronomers call a supernova.

The light from this explosion first reached Earth from the direction of the constellation Cassiopeia in about 1667 AD. If anyone alive at the time saw it, they left no records. It is likely that large amounts of dust between the dying star and Earth dimmed the brightness of the explosion to the point that it was barely, if at all, visible to the unaided eye.

The remnant of this supernova was discovered in 1947 from its powerful radio emission. Named Cassiopeia A, it is one of the brightest radio sources in the whole sky. More recently, the Spitzer Space Telescope detected infrared echoes of the flash of light rippling outwards from the supernova in a series of pictures taken over a few years. This infrared image from the Wide-field Infrared Survey Explorer, or WISE, also shows the light echoes of the Cassiopeia A supernova remnant.

In the image, the central bright cloud of dust is the blast wave moving through interstellar space heating up dust as it goes. The blast wave travels fast at an average speed of about 18,000 kilometers per second (11,000 miles per second) but that is still only about 6% of the speed of light. The blast has expanded out to about a distance of 21 light-years from the original explosion. The flash of light from the explosion traveled faster - at the speed of light - covering over 300 light-years at the time that WISE took this picture. The orange-colored echoes further out from the central remnant are from dust heated as the supernova flash reached the dust centuries after the original explosion.

The colors used in this image represent specific wavelengths of infrared light. Blue and cyan (blue-green) represent light emitted predominantly from stars at wavelengths of 3.4 and 4.6 microns. Green and red represent light mostly emitted by dust at 12 and 22 microns, respectively.

Image Source: http://wise.ssl.berkeley.edu/gallery_CassiopeiaA.html

Curator: Wide-field Infrared Survey Explorer, Berkeley, CA, USA

Image Use Policy: Pulic Domain

Image Details

Image Type
Observation
Object Name
Cassiopeia A Cas A
Subject - Milky Way
Nebula » Type » Supernova Remnant
Nebula » Type » Star Formation

Distance

Universescale1
11,000 light years
Wise_wise2012-002_128
 

Position Details

Position (ICRS)
RA = 23h 25m 12.5s
DEC = 59° 8’ 27.3”
Orientation
North is 89.8° CCW
Field of View
4.1 x 3.4 degrees
Constellation
Cassiopeia

Color Mapping

  Telescope Spectral Band Wavelength
Arrow_left_blue WISE Infrared (Near-IR) 3.4 µm
Arrow_left_cyan WISE Infrared (Near-IR) 4.6 µm
Arrow_left_green WISE Infrared (Mid-IR) 12.0 µm
Arrow_left_red WISE Infrared (Mid-IR) 22.0 µm
Spectrum_ir1
Arrow_top_blue
Arrow_top_cyan
Arrow_top_green
Arrow_top_red
Wise_wise2012-002_1280
×
ID
WISE2012-002
Subject Category
B.4.1.4   B.4.1.2  
Subject Name
Cassiopeia A, Cas A
Credits
NASA/JPL-Caltech/UCLA
Lightyears
11,000
Redshift
Reference Url
http://wise.ssl.berkeley.edu/gallery_CassiopeiaA.html
Type
Observation
Image Quality
Good
Distance Notes
Facility
WISE, WISE, WISE, WISE
Instrument
Color Assignment
Blue, Cyan, Green, Red
Band
Infrared, Infrared, Infrared, Infrared
Bandpass
Near-IR, Near-IR, Mid-IR, Mid-IR
Central Wavelength
3400, 4600, 12000, 22000
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
ICRS
Equinox
Reference Value
351.30190945000, 59.14091296400
Reference Dimension
5400.00, 4500.00
Reference Pixel
2386.67279582892, 1955.23357301565
Scale
-0.00076372134, 0.00076372134
Rotation
89.78104190124
Coordinate System Projection:
TAN
Quality
Full
FITS Header
Notes
Creator (Curator)
Wide-field Infrared Survey Explorer
URL
http://wise.astro.ucla.edu
Name
Email
outreach@ssl.berkeley.edu
Telephone
Address
7 Gauss Way
City
Berkeley
State/Province
CA
Postal Code
94720
Country
USA
Rights
Pulic Domain
Publisher
Publisher ID
WISE
Resource ID
Resource URL
/image/WISE/WISE2012-002
Related Resources
Metadata Date
2012-10-17 14:35:01 -0700
Metadata Version
1.2
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Detailed color mapping information coming soon...

 

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Universescalefull
11,000 light years