One of the hottest novae on record has been spotted exploding with a temperature of over 3 million °C (5.4 million °F).
Novae occur when a white dwarf steals material from a larger companion star.
The gas gathers on the white dwarf until it erupts. In some cases, the dwarf star then resumes its gas theft, restarting the cycle.
As well as being one of the hottest, the object, LMC86, is the first ‘recurring’ nova to be seen outside our Galaxy.
Located in the Large Magellanic Cloud (LMC), it erupts every four years and was extensively monitored during an explosion in August 2024.
Researchers made the first-ever observations of an object at such distance using near-infrared spectroscopy, which allowed them to examine the nova’s most extreme phase.
This revealed highly ionised silicon, shining much brighter than the Sun’s light across all wavelengths.
"The ionised silicon shining at almost 100 times brighter than the Sun is unprecedented," says Tom Geballe, a NOIRLab emeritus astronomer who took part in the study.
Even more surprising is that silicon seems to be the only ionised element.
"We would’ve expected to also see signatures of highly energised sulphur, phosphorus, calcium and aluminium."
This indicates unusually high temperatures, possibly due to its location in the LMC, where stars have much lower levels of heavy elements.
Simulations show these would allow stellar material to accumulate for longer, meaning they would ignite with more violence.
