It is the youngest known remnant of a supernova in our galaxy, whose light first reached Earth 340 years ago.
NASA
An international team of astronomers led by Purdue University (USA), obtained a detailed image of Cassiopeia A (Cas A), a stellar remnant of a supernova, located regarding 11,000 light years away. Cas A is invisible to the human eye from Earth, but it occupies the space that appears to be to the right of the last stroke of the ‘W’ that forms the constellation Cassiopeia. The image was captured in the near infrared by NASA’s James Webb Space Telescope. communicated this Friday.
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a new look
«I have spent 17 years studying the stars and their titanic explosions. I have used dozens of telescopes, both on the ground and in space, covering the electromagnetic spectrum from gamma rays to radio wavelengths,” says Danny Milisavljevic, a Purdue University professor who led the team. ‘And yet I was still not ready for the data that James Webb has provided. I am in awe of its quality and beauty,” he noted.
The compiled image shows large curtains of material, shaded in red and orange, where material from the star impinges on circumstellar gas and dust. Between those stripes, pops of pink show where the light elements, like oxygen, argon, and neon, glow. A large green bow on the right side of the image puzzles researchers. “We’ve dubbed it the ‘Green Monster,’ following Boston’s Fenway Park,” says Milisavljevic.
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Higher resolution images, especially in the infrared, give astronomers a clearer view of the intricacies of the structure. “Compared to previous infrared images, we see incredible details that we have not been able to access before,” says Tea Temim, a co-author from Princeton University (USA). “In Cas A, we can spatially resolve regions that have different gas compositions and look at what types of dust formed in those regions,” Temim said.
Supernovae as factories of chemical elements
Cassiopeia A is the youngest known remnant of a supernova in our galaxy, the light of which first reached Earth 340 years ago. “Cas A represents our best chance to look at the debris field of an exploded star and perform a kind of stellar autopsy to understand what kind of star was there beforehand and how that star exploded,” says Milisavljevic.
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During their lives, stars create a variety of light chemical elements essential for life, but additional, heavier and crucial elements are only created from the energy of supernovae bursts. These key elements spread out into space from the jumble of clouds of gas, dust, and other material left behind. Carl Sagan claimed that we are made of “star stuff.” “By understanding the process of exploding stars, we are reading the origin of our own history,” explains Milisavljevic.
