Researchers from the Indian Institute of Technology (IIT) – Guwahati, have found new and important clues to understand the death of massive stars.
The IIT-Guwahati researchers have also revealed the problems with the existing models.
The IIT-Guwahati researchers found the clues based on a study conducted in collaboration with researchers from Max Planck Institute for Physics, Munich in Germany and North Western University, USA.
The researchers found that all three species of the neutrinos from the supernovae are important, contrary to the common treatments with only two flavors.
The results of this crucial work have been recently published in the journal, Physical Review Letters (PRL).
The journal has garnered attention from the astrophysics community worldwide.
The research has been carried out by Dr Sovan Chakraborty, Assistant Professor in the Department of Physics of IIT – Guwahati, along with his research scholar, Madhurima Chakraborty, in collaboration with Dr Francesco Capozzi, Postdoctoral fellow at the Max Planck Institute for Physics, Munichand Dr Manibrata Sen, Postdoctoral fellow at the North Western University, USA.
The super explosions at the time of death of large massive stars are considered to be the cradle of birth for new stars and synthesis of the heavy elements in nature.
At the end of their life, the stars, especially massive ones, collapse resulting in an immense shock wave that causes the star to explode, briefly outshining any other star in its host galaxy.
“However, the mechanism of these super explosions is not yet completely solved and has remained one of the enigmas of nature”, said Dr Sovan Chakraborty, Assistant Professor in Department of Physics of IIT – Guwahati.
The existing supernovae models predicted that the mu & tau neutrinos & antineutrinos have very similar properties and are considered as a single species.
“This information is very crucial for the reason that in the extremely dense supernovae core neutrinos interact with other neutrinos and may interchange flavors. This conversion may happen rapidly (in nanosecond time scale) and flavor interchange can affect the supernovae process as the different flavors are emitted with different angular distribution. These ’fast’ conversions are nonlinear in nature and are not confronted in any other neutrino sources but supernovae. We for the first time did a non-linear simulation of fast conversion with ‘all’ the three neutrino flavors in supernovae,” said Dr Sovan Chakraborty.
Dr Manibrata Sen said, “These three flavor studies change the results dramatically in comparison to the existing two flavor results and can have major implications for particle and astrophysics of supernovae neutrinos.”
Dr Francesco Capozzi, presently a Postdoctoral fellow at the Virginia tech University, USA cautioned, “The models used in our research work too have some simplifications, more generic studies are being done by our team and other competing groups. The clearer answers will need more precise muon supernova simulations which are appearing to be one of the most promising solution to the problems of core collapse mechanism.”
Meanwhile, these new results indicates that the differences between the three flavors of neutrinos are all relevant, and ignoring the presence of any of the flavors gives an incomplete picture of fast flavor exchange.