James Webb shows details in supernova remnant Cassiopeia A and rings around Uranus
NASA, ESA and the Canadian Space Agency CSA have published an image of Cassiopeia A, a supernova remnant. Also shown is a picture of planet Uranus with clearly visible rings. Both objects were imaged by the James Webb Space Telescope.
The image of Cassiopeia A was taken with the Mid-Infrared Instrument of the James Webb Space Telescope. Compared to previous infrared images, there are according to a researcher many more details visible that people had not previously had access to. The colors are the result of infrared light ‘translated’ into wavelengths from the visible part of the spectrum.
According to the space agencies, these colors lead to a wealth of scientific information. For example, on the outside, especially on the left and at the top, apparently red and orange material is visible, which is caused by the emission of hot dust. This is where the ejecta from the exploded star slams into the surrounding gas and dust. More on the inside, pink clogs and buttons are visible; this is material from the star that has started to emit light through a mix of dust combined with heavy elements such as oxygen, argon and neon. The green has a shape and complexity that is unexpected to the scientists and difficult to fathom. Ilse De Looze of Ghent University, one of the researchers involved, says that all sources of the emissions are still being unravelled.
About 10 light-years across, Cassiopeia A is a known supernova remnant located 11,000 light-years from Earth in the constellation Cassiopeia. It is the result of an explosion of a huge star whose light is estimated to have reached us about 340 years ago. It is the youngest known remnant of an explosion of a very large star in our galaxy. Cassiopeia A gives scientists the best opportunity to look at the remnants of an exploded star and perform a star autopsy of sorts to understand what type of star was previously present and how it exploded.
The space agencies also have one image of Uranus published showing the hard-to-see rings of the ice planet. The planet’s faint dust rings have previously only been captured by the 1986 Voyager 2 spacecraft’s flyby and the specialized Earth-based William M. Keck Observatory. The current image from James Webb was taken with the telescope’s main camera, the NIRCam. It is an infrared image on which data from two filters at 1.4 and 3.0μm has been combined, which is shown in blue and orange respectively. Voyager 2 showed a blue-green ball in wavelengths in the visible spectrum with few features; in comparison, James Webb’s image contains much more detail. The telescope captured the image on Feb. 6.