Supernova's unusual light show reveals new cosmic processes
SN 2024bch, a Type II supernova spotted in January 2024 about 65 million light-years away, isn't behaving like most supernovas.
While its early light showed features that usually mean there's a dramatic clash between exploding star debris and surrounding gas, researchers found no real evidence of this happening as time went on.
Processes behind the light
After tracking the supernova for 140 days with ground and space telescopes, scientists discovered something unexpected.
Instead of shock interactions powering the show, it's mainly radioactive decay and hydrogen recombination—plus a process called Bowen fluorescence (where ultraviolet light gets helium atoms to pass energy to oxygen and nitrogen) creating those narrow emission lines.
This is the first time this effect has been seen as such a big player in this kind of supernova.
Implications of the findings
This discovery means some Type II supernovas might not produce high-energy neutrinos the way scientists thought—which could shake up how we use different signals (like neutrinos and light) together to study space explosions.
The findings are set to appear in Astronomy & Astrophysics.