Scientists have theoretically found previously unknown layers on stars that enhance the mystery of the mechanism through which neutron stars heat up.
In astronomy, neutron star is a star composed of neutrons. It is a celestial body consisting entirely of a very dense compact mass of neutrons, the remnant of a star that has collapsed under its own gravity.
It is a neutral elementary particle. Technically speaking, it is any of three stable neutral elementary particles of the lepton family with a zero rest mass and no charge. Neutrinos have a spin of 1/2.
Scientists have long thought that the surface of the neutron stars is heated up as a result of the nuclear reactions within the crust, the thick, solid, outermost layer of the star.
However, in the present study, scientists have reported previously unknown layers, where nuclear reactions within the crust cause rapid neutrino cooling. They are of the opinion that these layers could decrease or stop the heat coming from the deeper layers to the surface.
“These cooling layers are pretty shallow beneath the surface,” said Schatz, a professor of physics and astronomy. “If heat from deeper within the star comes up, it hits this layer and never makes it to the surface.”
On the sub-atomic level, scientists found that the process is significantly affected by the shape of the reacting nuclei.
“Many nuclei are round, and that suppresses the neutrino cooling,” said Sanjib Gupta, co-author and faculty member at IIT Ropar in India. “In this case, the nuclei are predicted by theorists to be ‘deformed,’ more football-shaped.”
There may be “an unknown local heating mechanism near the neutron star surface,” Researchers wrote.
Schatz said this finding results in more questions than answers.
“This completely changes the way we think about the question of the star’s hot surface,” he said. “It’s a big puzzle now.”
You can study the mechanism through the surface of the neutron stars heat up.
The mystery of neutron stars heats up – Eurekalert (http://goo.gl/1DibXZ)
H. Schatz et al. (2013). Strong neutrino cooling by cycles of electron capture and β− decay in neutron star crusts Nature DOI: 10.1038/nature12757