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Cassiopeia A (MIRI Image)

A roughly square image is rotated clockwise about 45 degrees, with solid black in the corners on the top left, top right, bottom left, and bottom right. Within the image is a circular-shaped nebula with complex structure. On the circle’s exterior, particularly at the top and left of the image, lie curtains of material glowing orange. Interior to this outer shell lies a ring of mottled filaments of bright pink studded with clumps and knots. At center right, a greenish loop extends from the right side of the ring into the central cavity. Translucent wisps of blue, green, and red appear throughout the image.

Cassiopeia A (Cas A) is a supernova remnant located about 11,000 light-years from Earth in the constellation Cassiopeia. It spans approximately 10 light-years. This new image uses data from Webb’s Mid-Infrared Instrument (MIRI) to reveal Cas A in a new light.

On the remnant’s exterior, particularly at the top and left, lie curtains of material appearing orange and red due to emission from warm dust. This marks where ejected material from the exploded star is ramming into surrounding circumstellar material. 

Interior to this outer shell lie mottled filaments of bright pink studded with clumps and knots. This represents material from the star itself, and likely shines due to a mix of various heavy elements and dust emission. The stellar material can also be seen as fainter wisps near the cavity’s interior.

A loop represented in green extends across the right side of the central cavity. Its shape and complexity are unexpected and challenging for scientists to understand.

This image combines various filters with the color red assigned to 25.5 microns (F2550W), orange-red to 21 microns (F2100W), orange to 18 microns (F1800W), yellow to 12.8 microns (F1280W), green to 11.3 microns (F1130W), cyan to 10 microns (F1000W), light blue to 7.7 microns (F770W), and blue to 5.6 microns (F560W). The data comes from general observer program 1947.  

MIRI was contributed by NASA and ESA, with the instrument designed and built by a consortium of nationally funded European Institutes (the MIRI European Consortium) and NASA’s Jet Propulsion Laboratory, in partnership with the University of Arizona.

About the Object

  • R.A. Position
    R.A. PositionRight ascension – analogous to longitude – is one component of an object's position.
    23:23:24.00
  • Dec. Position
    Dec. PositionDeclination – analogous to latitude – is one component of an object's position.
    +58:48:54.00
  • Constellation
    ConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.
    Cassiopeia
  • Distance
    DistanceThe physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.
    11,090 light-years
  • Dimensions
    DimensionsThe physical size of the object or the apparent angle it subtends on the sky.
    Image is about 24 light-years across

About the Data

  • Data Description
    Data DescriptionProposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
    Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.

    This image was created with Webb data from proposal: 1947 (D. Milisavljevic).

  • Instrument
    InstrumentThe science instrument used to produce the data.
    MIRI
  • Exposure Dates
    Exposure DatesThe date(s) that the telescope made its observations and the total exposure time.
    August 4, 2022
  • Filters
    FiltersThe camera filters that were used in the science observations.
    F560W, F770W, F1000W, F1130W, F1280W, F1800W, F2100W, F2550W
  • Object Name
    Object NameA name or catalog number that astronomers use to identify an astronomical object.
    Cassiopeia A; SNR G111.7-02.1
  • Object Description
    Object DescriptionThe type of astronomical object.
    Supernova remnant
  • Release Date
    April 7, 2023
  • Science Release
    Webb Reveals Never-Before-Seen Details in Cassiopeia A
    Read the release
  • Credit
    Image: NASA, ESA, CSA, Danny Milisavljevic (Purdue University), Tea Temim (Princeton University), Ilse De Looze (UGhent); Image Processing: Joseph DePasquale (STScI)

Downloads

  • Full Res (For Display), 4008 × 4009
    png (10.82 MB)
  • Full Res (For Print), 4008 × 4009
    tif (12.89 MB)
  • 2000 × 2000
    png (3.1 MB)
A roughly square image is rotated clockwise about 45 degrees, with solid black in the corners on the top left, top right, bottom left, and bottom right. Within the image is a circular-shaped nebula with complex structure. On the circle’s exterior, particularly at the top and left of the image, lie curtains of material glowing orange. Interior to this outer shell lies a ring of mottled filaments of bright pink studded with clumps and knots. At center right, a greenish loop extends from the right side of the ring into the central cavity. Translucent wisps of blue, green, and red appear throughout the image.
Color Info
Color InfoA brief description of the methods used to convert telescope data into the color image being presented.

These images are a composite of separate exposures acquired by the James Webb Space Telescope using the MIRI instrument. Several filters were used to sample wide wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are:   Blue: F560W, Light Blue: F770W, Cyan: F1000W, Green: F1130W, Yellow: F1280W, Orange: F1800W, Red: F2100W+F2550W

Compass and Scale
Compass and ScaleAn astronomical image with a scale that shows how large an object is on the sky, a compass that shows how the object is oriented on the sky, and the filters with which the image was made.

Related Images & Videos

An image labeled “James Webb Space Telescope, Cassiopeia A, SNR G111.7-02.1).” A roughly square image is rotated clockwise about 45 degrees, with solid black in the corners. Within the image is a roughly circular nebula with complex structure. On the circle’s exterior, particularly at the top and left, lie curtains of material glowing orange. Interior to this outer shell lies a ring of mottled filaments of bright pink studded with clumps and knots. At center right, a greenish loop extends from the right side of the ring into the central cavity. Translucent wisps of blue, green and red are throughout the image. At lower left, a scale bar is labeled 3 light-years and 1 arcminute. At lower right, a white arrow pointing up is labeled N for north, while an arrow pointing left is labeled E for east. At the bottom is a list of MIRI filters in different colors, from left to right: F560W, F770W, F1000W, F1130W, F1280W, F1800W, F2100W, and F2550W.

Cassiopeia A (MIRI Compass Image)

This image of the Cassiopeia A supernova remnant, captured by Webb’s Mid-Infrared Instrument (MIRI), shows compass arrows, scale bar, and color key for reference. The north and east compass arrows show the orientation of the image on the sky. Note that the relationship between...

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Details

Last Updated
Aug 28, 2025
Contact
Media

Laura Betz
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
laura.e.betz@nasa.gov

Image Credit

NASA, ESA, CSA, Danny Milisavljevic (Purdue University), Tea Temim (Princeton University), Ilse De Looze (UGhent)

Image Processing Credit

Joseph DePasquale (STScI)

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