Researchers using NASA’s James Webb Space Telescope have made major strides in confirming the source of dust in early galaxies. Observations of two type II supernovae, Supernova 2004et (SN 2004et) and Supernova 2017eaw (SN 2017eaw), have revealed large amounts of dust within their craters. The mass the researchers found supports the theory that supernovae played a key role in supplying dust to the early universe.

Dust is a building block for many things in our universe, particularly planets. As dust from dying stars spreads out into space, it carries key elements to help birth the next generation of stars and their planets. Where this dust comes from has puzzled astronomers for decades. An important source of cosmic dust could be supernovae, since after a dying star explodes, the remaining gas expands and cools to create dust.

“Direct evidence of this phenomenon has been minimal until now, with our capabilities only allowing us to study the amounts of dust in a relatively nearby supernova to date – Supernova 1987A, 170,000 light-years from Earth,” said lead author author Melissa Shahbandeh of John Hopkins University and the Space Telescope Science Institute in Baltimore, Maryland. “When the gas cools enough to form dust, that dust is only detectable at mid-infrared wavelengths, provided it has enough sensitivity.”

For supernovae more distant than SN 1987A, such as SN 2004et and SN 2017eaw, both in NGC 6946 about 22 million light-years away, this combination of wavelength coverage and exceptional sensitivity can only be achieved with Webb’s MIRI ( Mid-Infrared Instrument).

The Webb observations are the first major breakthrough in the study of supernova dust production since the detection of newly formed dust in SN 1987A with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope nearly a decade ago.

Another particularly interesting result of their study is not just the detection of dust, but the amount of dust detected at this early stage of the supernova’s life. In SN 2004et, researchers found more than 5,000 Earth masses of dust.

Observations have shown astronomers that young, distant galaxies are full of dust, but these galaxies are not large enough for intermediate-mass stars like the Sun to supply us with dust as they age.

While astronomers have confirmed that supernovae produce dust, the question remains about how much of that dust can survive the blast waves after the explosion. Seeing this amount of dust at this stage in the lifetime of SN 2004et and SN 2017eaw suggests that the dust can survive the shock wave and is proof that supernovae are really important dust factories after all.

SN 2004et and SN2017eaw are the first of five targets included in this program. The observations were completed as part of the Webb General Observer 2666 project. The work was published in the Monthly Notices of the Royal Astronomical Society on July 5.