Investigating the mechanisms underlying the formation of the universe

A thematic project brings together theoretical, observational and experimental research to study questions such as the origin of elements in the cosmos and the nuclear reactions behind stellar explosions.

By Heitor Shimizu, in New York  |  Agência FAPESP – Understanding how the stars and galaxy of our solar system were formed and how they will evolve is the challenge for a group of Brazilian scientists.  

With funding from FAPESP for the thematic project, CompStarBrazil group is investigating basic and fundamental questions about the existence and the future of the universe. 

Their objective is to try to find clues to one of the greatest enigmas of material physics: the exact conditions in nature under which the fundamental degrees of freedom of strongly interacting matter – quarks and gluons – as described by the theory of strong interactions known as Quantum Chromodynamics. These are the conditions present when the stars and universe itself were formed.

“The project involves theoretical, phenomenological and experimental/observational research seeking to characterize the state of matter at supranuclear densities and low temperatures,” said Jorge Ernesto Horvath, a professor in the Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG) of the University of São Paulo (USP), during FAPESP Week New York, organized jointly by the City University of New York (CUNY) and the Wilson Center November 26-28, 2018 at the Graduate Center of CUNY. 

“We are investigating exotic states (quark matter), the nature of magnetized neutron stars and white dwarfs, and alternative theories of gravity applied to compact objects,” Horvath said.    

“What are we talking about? A scenario far from terrestrial laboratory data. We are investigating roughly everything in space up to the highest density present anywhere in the universe,” Horvath said.  

He went on to explain that CompStarBrazil involves the work of four principal investigators, 10 research associates, six postdocs and 12 undergraduate students from the state of São Paulo. It also includes scientists from the Technological Institute of Aeronautics (ITA), the National Institute for Space Research (INPE), the Institute of Astronomy, Geophysics and Atmospheric Sciences at the University of São Paulo (IAG-USP), the USP Physics Institute, the Federal University of the ABC, the Federal University of São Paulo and São Paulo State University.

“We also have a large number of collaborators in Brazil and abroad,” said Horvath, one of the thematic project’s principal investigators. The project is led by ITA Professor Manuel Máximo Bastos Malheiro de Oliveira. 

“We are investigating possible explanations for what we call millennial problems in astrophysics, including those regarding the nature of neutron stars and dense nuclear matter, the origin of the elements in the cosmos, and the nuclear reactions that drive stars and stellar explosions,” said Horvath.

The lines of research under the thematic project include such things as: the composition of the interior of neutron stars and of quarks and their structure; the modeling of the formation of compact stars in supernovas and surges of gamma rays; pulsars, magnetars and magnetized white dwarfs; gravitational waves; alternative theories of gravity; and implications on superdense matter in the universe.    

According to project researchers, the fundamental degrees of freedom were present at the very start of the universe, which underwent a process that confined the quarks and gluons to the point at which their temperature dropped to around 160 MeV (megaelectron-volts), resulting in the formation of ordinary hadronic matter.  

There are sites in the present-day universe where scientists hope to find fundamental degrees of freedom of hadronic matter similar to those that occurred when the universe was formed, such as the interior of superdense stars, where temperatures can reach as high as 10 billion degrees Kelvin and the density exceeds the value of nuclear matter saturation density.  

Horvath points out that investigations of something as complex as this is only possible using an unlimited number of investigative approaches and tools, both theoretical and observational. Because of that, the CompStarBrazil studies involve a comprehensive series of research lines aimed at increasing the knowledge of compact stars and their interiors. The idea is to achieve a theoretical breakthrough that explains the phenomenology of these compact objects and allows a better understanding of the processes that led to the formation of the universe.   

For more information about FAPESP Week New York, visit: www.fapesp.br/week2018/newyork.