Webb Focuses on Supernova 1987A Remnant

Astronomers using the NASA/ESA/CSA James Webb Space Telescope have begun the study of SNR 1987A, one of the most renowned supernova remnants.

This image of SNR 1987A was taken with Webb’s Near-Infrared Camera. At the center, material ejected from the supernova forms a keyhole shape. Just to its left and right are faint crescents newly discovered by Webb. Beyond them an equatorial ring, formed from material ejected tens of thousands of years before the supernova explosion, contains bright hot spots. Exterior to that is diffuse emission and two faint outer rings. Image credit: NASA / ESA / CSA / M. Matsuura, Cardiff University / R. Arendt, NASA’s Goddard Spaceflight Center & University of Maryland, Baltimore County / C. Fransson.

SN 1987A was first observed on February 23, 1987 at the edge of the Large Magellanic Cloud, some 163,000 light-years away.

It was the first naked-eye supernova to be observed since Johannes Kepler witnessed a supernova over 400 years ago.

Because of its relative proximity to Earth, SN 1987A’s remnant is by far the best-studied supernova remnants of all time.

The new observations from Webb’s Near-Infrared Camera (NIRCam) provide a crucial clue to the understanding of how a supernova develops over time to shape its remnant.

“The new Webb image reveals a central structure like a keyhole,” Webb astronomers said.

“This center is packed with clumpy gas and dust ejected by the supernova explosion.”

“The dust is so dense that even near-infrared light that Webb detects can’t penetrate it, shaping the dark ‘hole’ in the keyhole.”

“A bright, equatorial ring surrounds the inner keyhole, forming a band around the waist that connects two faint arms of hourglass-shaped outer rings.”

“The equatorial ring, formed from material ejected tens of thousands of years before the supernova explosion, contains bright hot spots, which appeared as the supernova’s shock wave hit the ring.”

“Now spots are found even exterior to the ring, with diffuse emission surrounding it. These are the locations of supernova shocks hitting more exterior material.”

While these structures have been observed to varying degrees by the NASA/ESA Hubble Space Telescope, NASA’s Spitzer Space Telescopes and Chandra X-ray Observatory, the unparalleled sensitivity and spatial resolution of Webb revealed a new feature in SNR 1987A — small crescent-like structures.

“These crescents are thought to be a part of the outer layers of gas shot out from the supernova explosion,” the astronomers said.

“Their brightness may be an indication of limb brightening, an optical phenomenon that results from viewing the expanding material in three dimensions.”

“In other words, our viewing angle makes it appear that there is more material in these two crescents than there actually may be.”

Before Webb, the now-retired Spitzer telescope observed SNR 1987A in infrared throughout its entire lifespan, yielding key data about how its emissions evolved over time.

However, it was never able to observe the supernova remnant with such clarity and detail.

“Despite the decades of study since the supernova’s initial discovery, there are several mysteries that remain, particularly surrounding the neutron star that should have been formed in the aftermath of the supernova explosion,” the researchers said.

“Like Spitzer, Webb will continue to observe SNR 1987A over time.”