Celestial hemisphere:  Northern  ·  Constellation: Cassiopeia (Cas)
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Cas A, John Bozeman
Cas A
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Cas A

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Cas A, John Bozeman
Cas A
Powered byPixInsight

Cas A

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Description

Cassiopeia A  is a supernova remnant (SNR) in the constellation Cassiopeia and the brightest extrasolar radio source in the sky at frequencies above 1 GHz. The supernova occurred approximately 11,000 light-years (3.4 kpc) away within the Milky Way; given the width of the Orion Arm, it lies in the next-nearest arm outwards, the Perseus Arm, about 30 degrees from the Galactic anticenter. The expanding cloud of material left over from the supernova now appears approximately 10 light-years (3 pc) across from Earth's perspective. It has been seen in wavelengths of visible light with amateur telescopes down to 234 mm (9.25 in) with filters.

It is estimated that light from the supernova itself first reached Earth near the 1690s, although there are no definitively corresponding records from then. Cas A is circumpolar at and above mid-Northern latitudes which had extensive records and basic telescopes. Its likely omission in records is probably due to interstellar dust absorbing optical wavelength radiation before it reached Earth, although it is possible that it was recorded as a sixth magnitude star 3 Cassiopeiae by John Flamsteed. Possible explanations lean toward the idea that the source star was unusually massive and had previously ejected much of its outer layers. These outer layers would have cloaked the star and re-absorbed much of the light released as the inner star collapsed.

Data from the James Webb Space Telescope MAST Portal. Release date: 2023-11-07

Camera: NIRCAM

Color Mapped:

Red-F444W
Green-F356W
Blue-F356W

Processed with FITS Liberator, GraXpert, PixInsight and Photoshop 2024.

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Cas A, John Bozeman