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Thousands of years ago, a star in our galaxy violently exploded and created the glowing remnant of a supernova called Cassiopeia A, which has intrigued scientists for decades.
And now a new picture It was captured by the James Webb Space Telescope The closest and most detailed image has been revealed inside the exploded star, according to astronomers. Image analysis can help researchers better understand the processes that fuel these massive incendiary events.
The space observatory also allowed astronomers to glimpse mysterious features that were not visible in images of the remnants taken with telescopes such as Hubble, Chandra, Spitzer, or other Webb instruments.
The new image was shared on Monday by First Lady Dr. Jill Biden when she debuted the first-ever digital photo White House Advent Calendarwhich includes Webb’s new perspective of Cassiopeia A that appears to shine like a Christmas decoration.
“We’ve never seen this kind of look at an exploding star before,” astronomer Dan Milisavljevic, an assistant professor of physics and astronomy at Purdue University, said in a statement. “Supernovas are fundamental drivers of cosmic evolution. Energies and their chemical abundances – there’s a lot that depends on our understanding of supernovas. This is the closest look we’ve ever had at a supernova in our galaxy.”
Swirls of gas and dust are all that’s left of the star that went supernova 10,000 years ago. Cassiopeia A is located 11,000 light-years away in the constellation Cassiopeia. a Light yearEquivalent to 5.88 trillion miles (9.46 trillion kilometers), which is the distance a ray of light travels in one year.
Light from Cassiopeia A first reached Earth about 340 years ago. As the smallest known supernova remnant in our galaxy, this celestial body has been studied by many ground-based and space telescopes. The rest extends about 10 light-years, or 60 trillion miles (96.6 trillion kilometers).
Insights from Cas A, as the remnant is also known, allow scientists to learn more about the life cycle of stars.
Astronomers used a near-infrared web camera, called NIRCam, to view the supernova remnant at different wavelengths of light than those used in previous observations. The image shows unprecedented detail of the interaction between the expanding envelope of material generated by the supernova as it collides with the gas released by the star before the explosion.
But the picture seems complete Different from the one Webb took in April Using the telescope’s mid-infrared instrument, or MIRI. In each photo, certain features stand out that are not visible in the other photo.
Webb observes the universe at wavelengths of infrared light, which are invisible to the human eye. As scientists process Webb’s data, the light captured by the telescope is translated into a spectrum of colors visible to humans.
The new NIRCam image is dominated by flashes of orange and bright pink within the supernova remnant’s inner shell. The colors correspond to gaseous knots of elements shed by the star, including oxygen, argon, neon and sulfur. Mixed within the gas are dust and particles. Eventually, all these ingredients will come together to form new stars and planets.
Studying the remains allows scientists to reconstruct what happened during the supernova.
“Thanks to the resolution of NIRCam, we can now see how the dying star completely shattered as it exploded, leaving behind filaments that resemble tiny glass shards,” Milisavljevic said. “It is truly incredible that after all these years of studying Cas A we can now resolve these details, which provide us with transformative insight into how this star exploded.”
When comparing the NIRCam image with the MIRI image taken in April, the new perspective looks less colorful. The bright orange-red swirls from the April image appear smokier through NIRCam’s eyes, showing where the shock wave from the supernova collided with surrounding material.
The white light in the NIRCam image is due to synchrotron radiation, which is created when charged particles accelerate and travel around magnetic field lines.
Astronomers have observed previously unseen details in the Cassiopeia A supernova remnant using the Webb Telescope’s near-infrared camera (left) and the mid-infrared instrument (right).
The main feature missing from the NIRCam view is the “green monster” from the MIRI image, or a circle of green light at the center of the remnant, which has puzzled and challenged astronomers.
But new details can be seen in the near-infrared image that shows circular holes surrounded by white and purple, outlining charged particles of debris that make up the gas that the star released before it exploded.
Another new feature in the NIRCam image is a bubble called Baby Cas A that can be seen in the lower right corner, which appears to be the offspring of a larger supernova remnant and is located 170 light-years behind Cassiopeia A.
Baby Cas A is actually a feature called a light echo, where supernova light interacts with dust and causes it to heat up. The dust continues to glow as it cools over time.
“It’s amazing,” said Milisavljevic, who led the project team that contributed to the new image. “Some completely new features have emerged, which will change the way we think about the life cycles of stars.”
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