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Like a shiny, round ornament ready to be placed in the perfect spot on a holiday tree, supernova remnant Cassiopeia A (Cas A) gleams in a new image from NASA\u2019s James Webb Space Telescope. As part of the\u00a02023 Holidays at the White House, First Lady of the United States Dr. Jill Biden debuted the first-ever White House Advent Calendar. To showcase the \u201cMagic, Wonder, and Joy\u201d of the holiday season, Dr. Biden and NASA are celebrating with this new image from Webb.<\/p>\n
While all is bright, this scene is no proverbial silent night.\u00a0Webb\u2019s NIRCam (Near-Infrared Camera) view of Cas A displays this stellar explosion at a resolution previously unreachable at these wavelengths. This high-resolution look unveils intricate details of the expanding shell of material slamming into the gas shed by the star before it exploded.<\/p>\n
Cas A is one of the most well-studied supernova remnants in all of the cosmos. Over the years, ground-based and space-based observatories, including NASA\u2019s Chandra X-Ray Observatory, Hubble Space Telescope, and retired Spitzer Space Telescope have assembled a multiwavelength picture of the object\u2019s remnant.<\/p>\n
However, astronomers have now entered a new era in the study of Cas A. In April 2023, Webb\u2019s MIRI (Mid-Infrared Instrument) started this chapter, revealing new and unexpected features within the inner shell of the supernova remnant. Many of those features are invisible in the new NIRCam image, and astronomers are investigating why.<\/p>\n
Infrared light is invisible to our eyes, so image processors and scientists translate these wavelengths of light to visible colors. In this newest image of Cas A, colors were assigned to different filters from NIRCam, and each of those colors hints at different activity occurring within the object.<\/p>\n
At first glance, the NIRCam image may appear less colorful than the MIRI image. However, this simply comes down to the wavelengths in which the material from the object is emitting its light.<\/p>\n
The most noticeable colors in Webb\u2019s newest image are clumps represented in bright orange and light pink that make up the inner shell of the supernova remnant. Webb\u2019s razor-sharp view can detect the tiniest knots of gas, comprised of sulfur, oxygen, argon, and neon from the star itself. Embedded in this gas is a mixture of dust and molecules, which will eventually become components of new stars and planetary systems. Some filaments of debris are too tiny to be resolved by even Webb, meaning they are comparable to or less than 10 billion miles across (around 100 astronomical units). In comparison, the entirety of Cas A spans 10 light-years across, or 60 trillion miles.<\/p>\n
\u201cWith NIRCam\u2019s resolution, we can now see how the dying star absolutely shattered when it exploded, leaving filaments akin to tiny shards of glass behind,\u201d said Danny Milisavljevic of Purdue University, who leads the research team. \u201cIt\u2019s really unbelievable after all these years studying Cas A to now resolve those details, which are providing us with transformational insight into how this star exploded.\u201d<\/p>\n
When comparing Webb\u2019s new near-infrared view of Cas A with the mid-infrared view, its inner cavity and outermost shell are curiously devoid of color.<\/p>\n
The outskirts of the main inner shell, which appeared as a deep orange and red in the MIRI image, now look like smoke from a campfire. This marks where the supernova blast wave is ramming into surrounding circumstellar material. The dust in the circumstellar material is too cool to be detected directly at near-infrared wavelengths, but lights up in the mid-infrared.<\/p>\n
Researchers say the white color is light from synchrotron radiation, which is emitted across the electromagnetic spectrum, including the near-infrared. It\u2019s generated by charged particles traveling at extremely high speeds spiraling around magnetic field lines. Synchrotron radiation is also visible in the bubble-like shells in the lower half of the inner cavity.<\/p>\n
Also not seen in the near-infrared view is the loop of green light in the central cavity of Cas A that glowed in mid-infrared, nicknamed the Green Monster by the research team. This feature was described as \u201cchallenging to understand\u201d by researchers at the time of their first look.<\/p>\n
While the \u2018green\u2019 of the Green Monster is not visible in NIRCam, what\u2019s left over in the near-infrared in that region can provide insight into the mysterious feature. The circular holes visible in the MIRI image are faintly outlined in white and purple emission in the NIRCam image \u2013 this represents ionized gas. Researchers believe this is due to the supernova debris pushing through and sculpting gas left behind by the star before it exploded.<\/p>\n
Researchers were also absolutely stunned by one fascinating feature at the bottom right corner of NIRCam\u2019s field of view. They\u2019re calling that large, striated blob Baby Cas A \u2013 because it appears like an offspring of the main supernova.<\/p>\n
This is a light echo, where light from the star\u2019s long-ago explosion has reached and is warming distant dust, which is glowing as it cools down. The intricacy of the dust pattern, and Baby Cas A\u2019s apparent proximity to Cas A itself, are particularly intriguing to researchers. In actuality, Baby Cas A is located about 170 light-years behind the supernova remnant.<\/p>\n
There are also several other, smaller light echoes scattered throughout Webb\u2019s new portrait.<\/p>\n
The Cas A supernova remnant is located 11,000 light-years away in the constellation Cassiopeia. It\u2019s estimated to have exploded about 340 years ago from our point of view.<\/p>\n
The James Webb Space Telescope is the world\u2019s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.<\/em><\/p>\n Laura\u00a0Betz<\/strong> \u2013 laura.e.betz@nasa.gov, Rob Gutro<\/strong>\u2013 rob.gutro@nasa.gov Hannah Braun <\/strong>\u2013 hbraun@stsci.edu , Christine Pulliam<\/em><\/strong><\/em> \u2013 cpulliam@stsci.edu Download full resolution images for this article<\/strong> from the Space Telescope Science Institute.<\/p>\n View\/download a video tour of Cassiopeia A <\/strong> from the Space Telescope Science Institute.<\/p>\n Right click the images in this article to open a larger version in a new tab\/window.<\/p>\n Lifecycle of Stars<\/strong><\/p>\n More Webb News<\/strong> \u2013 <\/p>\n More Webb Images<\/strong> \u2013 <\/p>\n Webb Mission Page<\/strong> \u2013 <\/p>\n What is a supernova?<\/strong><\/p>\n What is a nebula?<\/p>\n What is the Webb Telescope?<\/strong><\/p>\nMedia Contacts<\/h2>\n
NASA\u2019s \u00a0Goddard Space Flight Center<\/em>,\u00a0<\/em>, Greenbelt, Md.<\/p>\n
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