Last week at the 245th meeting of the American Astronomical Society in National Harbor, Maryland, astronomers presented some of their most recent and exciting finds from the James Webb Space Telescope (JWST). One such discovery was the identification of the most distant so-called core-collapse supernova ever confirmed. These explosions mark the end of life for massive stars, and this supernova occurred when the universe was just a toddler, some 1.8 billion years old.
Diving into the data
David Coulter, a postdoc at the Space Telescope Science Institute (STScI), studied numerous images from JWST’s Advanced Deep Extragalactic Survey (JADES) program, which targets and characterizes the earliest galaxies. Coulter and his team captured images up to a year apart with the Near Infrared Camera.
The team uncovered supernova cataloged as AT2023 ADS-V, along with more than 80 other transients (objects that vary in luminosity over time). In the case of AT2023 ADS-V, images from 2022 and 2023 allowed astronomers to compare the star’s behavior over that interval.
A deep find
When a massive star exhausts all its fuel for nuclear fusion, an imbalance of forces causes the star to collapse in on itself and then explode outward, which is categorized as a type II supernova. Stars must be at least eight times our Sun’s mass to undergo such a transformation. In this case, astronomers estimate the mass of AT2023 ADS-V’s progenitor at a gargantuan 20 solar masses, a real behemoth.
AT2023 ADS-V’s long-ago environment contained only one-third of the amount of heavy elements — those with more protons than hydrogen and helium — found in today’s “older” local universe. Heavy elements are made through fusion in the cores of massive stars, which then explode as supernovae, enriching the cosmos with them.
AT2023 ADS-V is just one of many transients discovered in JADES. “This is really our first sample of what the high-redshift universe looks like for transient science,” said study team member Justin Pierel, also at STScI, in a press release. “We are trying to identify whether distant supernovae are fundamentally different from or very much like what we see in the nearby universe.”
Certainly yet more early stellar explosions will also be discovered. And they will no doubt give astronomers a fuller picture of the early days of the universe, when simplicity was beginning to give way to a more complex, richer cosmos filled with heavier elements, and ultimately leading to the emergence of life.
