Scientists thought they understood how neutron stars self-heated, but new research suggests it's time for them to rework their theory.
A neutron star is "a super dense star that forms when a large star explodes and its core collapses into itself," a Michigan State University news release reported. Researchers previously believed the warming effect was caused by nuclear reactions within the star's crust.
A research team used theoretical calculations to pinpoint previously-unknown layers where "nuclear reactions within the crust cause rapid neutrino cooling."
Neutrinos are elementary particles that are created by radioactive decay. These particles have the ability to pass through matter extremely quickly.
"These cooling layers are pretty shallow beneath the surface," Hendrik Schatz, a professor of physics and astronomy, said. "If heat from deeper within the star comes up, it hits this layer and never makes it to the surface."
Schatz said these findings cause more confusion, instead of straightening up the theory. Researchers now have more questions about the process than ever before.
"This completely changes the way we think about the question of the star's hot surface," he said. "It's a big puzzle now."
The team determined the process significantly manipulated the shape of the nuclei on a subatomic level.
"Many nuclei are round, and that suppresses the neutrino cooling," Sanjib Gupta, co-author and faculty member at IIT Ropar in India, said. "In this case, the nuclei are predicted by theorists to be 'deformed,' more football-shaped."
A new facility on the MSU campus called the Facility for Rare Isotope Beams (FRIB) will allow researchers to examine this type of nuclei.
"This work was enabled by the Joint Institute for Nuclear Astrophysics. JINA is a National Science Foundation Physics Frontiers Center on Nuclear Astrophysics that promotes collaboration between astrophysicists and nuclear physicists. MSU is one of the core institutions of JINA," the news release reported.
