The James Webb Space Telescope (JWST) has taken some new images of a star that exploded during the Reagan Administration. The space telescope’s NIRCam (Near-Infrared Camera) helped capture the images of a world renowned supernova called Supernova 1987A (SN 1987A) in September 2022. The jaw-dropping new images were officially made public on August 31.
Supernova 1987A is roughly 168,000 light-years away from Earth and located in the Large Magellanic Cloud–a satellite dwarf galaxy of the Milky Way. The supernova is the remnants of a blue supergiant star called Sanduleak–69 202. It was believed to hold a mass about 20 times that of the sun before the explosion was detected in February 1987. It is also the closest observed supernova since 1604, when Kepler’s Supernova illuminated the Milky Way. Supernova 1987A has been the target of observations at wavelengths ranging from gamma rays to radio waves for nearly 40 years.
The latest image shows a central structure of inner ejecta similar to a keyhole. Clumpy gas and dust pack up the center that is ejected by the supernova explosion. According to NASA, the dust is so dense that even near-infrared light that Webb can detect can’t penetrate it, shaping the dark “hole” in the keyhole.
Surrounding the inner keyhole is a bright equatorial ring which forms a band around the “waist” of the supernova which connects the two faint arms of hourglass-shaped outer rings. The equatorial ring is formed from material ejected tens of thousands of years before the supernova even exploded.. Bright hot spots in the ring appeared as the supernova’s shock wave hit it, and now exist externally to the ring, with diffuse emission surrounding it. These are where the supernova shocks hit more exterior material.
The Hubble and Spitzer Space Telescopes and the Chandra X-ray Observatory have also observed Supernova 1987A, but JWST’s sensitivity and spatial resolution abilities showed a new feature in this supernova remnant–small crescent-like structures. The crescents are believed to be part of the outer layers of gas that shot out from the supernova explosion. They are very bright, which may be an indication of an optical phenomenon called limb brightening. This results from being able to observe the expanding material in three dimensions. “The viewing angle makes it appear that there is more material in these two crescents than there actually may be,” NASA wrote in a press release.
Before JWST, the now-retired Spitzer telescope observed this supernova in infrared throughout its entire 16 year lifespan, providing astronomers with key data about how Supernova 1987A’s emissions evolved over time. However, Spitzer couldn’t observe the supernova with the same level of clarity and detail as JWST.
There are still several mysteries surrounding this supernova, namely some unanswered questions about the neutron star that should have formed in the aftermath of the supernova explosion. There is some indirect evidence for the neutron star in the form of X-ray emission that was detected by NASA’s Chandra and NuSTAR X-ray observatories. Additionally, some observations taken by the Atacama Large Millimeter/submillimeter Array indicate the neutron star may be hidden within one of the dust clumps at the heart of the remnant.
JWST will continue to observe the supernova over time, using the NIRSpec (Near-Infrared Spectrograph) and MIRI (Mid-Infrared Instrument) instruments that give astronomers the ability to capture new, high-fidelity infrared data over time.