Starship Asterisk*

Images from NASA’s James Webb Space Telescope reveal large amounts of dust
within Supernova 2004et and Supernova 2017eaw. These supernovae are located
in spiral galaxy NGC 6946, 22 million light-years away from Earth.
Credit: NASA/ESA/CSA/Ori Fox, Melissa Shahbandeh, & Alyssa Pagan (STScI)

This image from the Kitt Peak National Observatory of NGC 6496 contextualizes
the locations of Supernova 2004et and Supernova 2017eaw within the galaxy.
Credits: KPNO, NOIRLab, NSF, AURA, Alyssa Pagan (STScI)

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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 the ejecta of each of these objects. The mass found by researchers 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 – planets in particular. As dust from dying stars spreads through space, it carries essential elements to help give birth to the next generation of stars and their planets. Where that dust comes from has puzzled astronomers for decades. One significant source of cosmic dust could be supernovae – after the dying star explodes, its leftover gas expands and cools to create dust.

“Direct evidence of this phenomenon has been slim up to this point, with our capabilities only allowing us to study the dust population in one relatively nearby supernova to date – Supernova 1987A, 170,000 light-years away from Earth,” said lead author Melissa Shahbandeh ... “When the gas cools enough to form dust, that dust is only detectable at mid-infrared wavelengths provided you have enough sensitivity.”

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

The Webb observations are the first breakthrough in the study of dust production from supernovae 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 intriguing result of their study isn’t just the detection of dust, but the amount of dust detected at this early stage in the supernova’s life. In SN 2004et, the researchers found more than 5,000 Earth masses of dust.

“When you look at the calculation of how much dust we’re seeing in SN 2004et especially, it rivals the measurements in SN 1987A, and it’s only a fraction of the age,” added program lead Ori Fox ... “It’s the highest dust mass detected in supernovae since SN 1987A.” ...

• arXiv > astro-ph > arXiv:2301.10778 > 25 Jan 2023