Webb discovers dust reservoirs in two supernovae

NASA James Webb space telescope reveals a dust source in early galaxies,


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Supernova (SN) explosions have been studied for decades as a potential source of cosmic dust that gives rise to galaxies, stars, and planetary systems. 

Researchers have made substantial progress in confirming the source of dust in early galaxies using NASA‘s James Webb Space Telescope. Observations of two Type II supernovae, Supernova 2004et (SN 2004et) and Supernova 2017eaw (SN 2017eaw), have revealed significant amounts of dust in their ejecta. The mass discovered by researchers backs up the hypothesis that supernovae were important in feeding dust to the early universe.

Many things in our universe, especially planets, are made of dust. As dust from dead stars spreads through space, it carries vital components that will aid in forming the next generation of stars and planets.

Since they have only been able to investigate the dust population in one relatively close supernova, Supernova 1987A, located 170,000 light-years from Earth, there is currently little direct evidence of this occurrence.

The researcher said, “When the gas cools enough to form dust, that dust is only detectable at mid-infrared wavelengths provided you have enough sensitivity.”

This combination of wavelength coverage and exceptional sensitivity is only possible with Webb’s MIRI (Mid-Infrared Instrument) for supernovae farther out than SN 1987A, such as SN 2004et and SN 2017eaw, both in NGC 6946 and located around 22 million light-years away.

Since the Atacama Large Millimeter/submillimeter Array (ALMA) telescope discovered newly generated dust in SN 1987A over ten years ago, the Webb findings represent the first significant advancement in the study of dust creation from supernovae. The researchers in SN 2004et discovered more than 5,000 Earth masses of dust. 

Lead author Melissa Shahbandeh of Johns Hopkins University and the Space Telescope Science Institute in Baltimore, Maryland, said, “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 of the Space Telescope Science Institute. It’s the highest dust mass detected in supernovae since SN 1987A.”

Astronomers have discovered that newborn, far-off galaxies are awash in dust. Yet, these galaxies are too young to have been replenished with dust over time by intermediate-mass stars like the Sun. More massive, short-lived stars may have perished sooner and in more significant quantities to produce that much dust. 

Astronomers have established that supernovae generate dust, but it is still unknown how much of that dust will endure the internal shocks that will reverberate in the wake of the explosion. Supernovae are key dust producers, as evidenced by the presence of this much dust at this point in the lives of SN 2004et and SN 2017eaw. This shows that dust can survive the shockwave.

Researchers also note that current mass estimates may only represent the tip of the iceberg. While Webb has enabled researchers to measure dust at lower temperatures than ever before, there may be unreported, colder particles radiating much further into the electromagnetic spectrum that is masked by the dust’s outermost layers.

New results are just a taste of Webb’s newly discovered study capabilities into supernovae, their dust creation, and what they can tell us about the stars from which they arose.

There is rising interest in understanding what this dust suggests about the exploding star’s core. After reviewing these discoveries, our colleagues will think of novel ways to interact with these dusty particles.

Journal Reference:

  1. Shahbandeh, M., Sarangi, A.,et al. JWST observations of dust reservoirs in type IIP supernovae 2004et and 2017eaw. Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/stad1681