NGC 6946, located 22 million light-years away from Earth, has earned the nickname “Fireworks Galaxy” due to the numerous supernovae observed within its arms. Two of these supernovae, SN 2004et and SN 2017eaw, have been studied using the James Webb Space Telescope’s MIRI (Mid-Infrared Instrument), leading to surprising findings. Researchers discovered significant amounts of dust within the remnants of these supernovae, supporting the theory that supernovae played a crucial role in providing dust to the early universe.
Dust, a vital component in the formation of celestial bodies like planets, has long puzzled astronomers in terms of its origin. One potential source of cosmic dust is supernovae. When a dying star explodes, its remaining gas expands and cools, forming dust as a byproduct. However, direct evidence of this phenomenon has been limited until now, with Supernova 1987A being the only nearby supernova in which dust population has been studied.
Observations made by the James Webb Space Telescope, specifically using the MIRI instrument, have provided breakthrough insights into the production of dust by supernovae. This marks a significant advancement since the detection of newly formed dust in Supernova 1987A nearly a decade ago with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope.
The researchers not only detected dust in SN 2004et and SN 2017eaw but also found a substantial amount of it in the early stages of the supernova’s life. In SN 2004et alone, the researchers estimated the presence of over 5,000 Earth masses of dust, rivaling the measurements in SN 1987A. These findings suggest that more massive stars, which have shorter lifespans, may have produced substantial amounts of dust before dying.
The survival of dust in the aftermath of a supernova’s shockwave has been a subject of inquiry for astronomers. The detection of significant dust quantities at this stage in the lifetimes of SN 2004et and SN 2017eaw implies that dust can endure the shockwave, supporting the idea that supernovae serve as important dust factories.
The researchers also believe that the current estimations of dust mass may only scratch the surface, as colder dust emitting farther into the electromagnetic spectrum may remain obscured by outer layers of dust. The new findings hint at the expanded research capabilities enabled by the James Webb Space Telescope, providing insights into supernovae and their dust production, as well as the stars from which they originated.
This study examined SN 2004et and SN 2017eaw, the first two targets in a program that includes a total of five objects. The observations were part of the Webb General Observer program 2666, and the research was published in the Monthly Notices of the Royal Astronomical Society.