Gravity waves reveal thermal secrets in neutron star mergers

binary simulation neutron star The merger shows that future detectors will differentiate between different models of thermonuclear matter.

Researchers use supercomputer simulations to explore how neutron star mergers affect gravity waves, find the critical relationship with the residue temperature. This research could contribute to future advances in detecting and understanding thermonuclear matter.

Exploring neutron star mergers and gravitational waves

When two neutron stars orbit each other, they release ripples in space-time called gravity waves. These ripples consume energy in orbit until the two stars eventually collide and merge into a single object. Scientists used supercomputer simulations to explore how the behavior of different models of nuclear matter affects the gravity waves released after these mergers. They found a strong correlation between the temperature of the remains and the frequency of these gravity waves. Next-generation detectors will be able to distinguish between these models.

Plots comparing the density (right) and temperature (left) of two different simulations of a neutron star merger (top and bottom) about 5 milliseconds after the merger, as shown above.Photo credit: Jacob Fields, Penn State University

Neutron Star: Nuclear Matter Laboratory

Scientists use neutron stars as laboratories to study nuclear material in conditions undetectable on Earth. They used current gravitational wave detectors to observe neutron star mergers and understand the behavior of cold, ultra-dense matter. However, these detectors cannot measure the signal from the merger of stars. This signal contains information about thermonuclear matter. Future detectors will be even more sensitive to these signals. Because they are also able to distinguish between different models, the results of this study suggest that the upcoming detectors will help scientists create better models of thermonuclear matter.

Detailed analysis of neutron star mergers

The study examined neutron star mergers using THC_M1, a computer code used to simulate neutron star mergers and account for the curvature of space-time due to the strong gravitational fields of stars and neutrino processes in dense matter. The researchers tested the thermal effects of the merger by varying the specific heat capacity in the equation of state, which measures the energy required to raise the temperature of the neutron star’s material by one degree. To ensure the robustness of the results, the researchers performed simulations at two resolutions. They repeated the higher-resolution run with a more approximate treatment of neutrinos.

refer to:

“Thermal effects in binary neutron star mergers” by Jacob Fields, Aviral Prakash, Matteo Breschi, David Radice, Sebastiano Bernuzzi and André da Silva Schneider, July 31, 2023 this Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/ace5b2

“Identification of nuclear effects in neutrino-carbon interactions under low three-momentum transfer”, February 17, 2016 Physical Review Letters.
DOI: 10.1103/PhysRevLett.116.071802

Funding: This research was funded primarily by the Nuclear Physics Program of the Department of Energy’s Office of Science. Additional funding was provided by the National Science Foundation and the European Union.

This work used computing resources provided by the National Energy Research Scientific Computing Center, the Pittsburgh Supercomputing Center, and Penn State’s Institute for Computational and Data Sciences.