Date:

Merging neutron stars

The option to measure the gravitational waves of two merging neutron stars has offered the chance to answer some of the fundamental questions about the structure of matter.

At the extremely high temperatures and densities in the merger scientists conjecture a phase-transition where neutrons dissolve into their constituents: quarks and gluons. In the current issue of Physical Review Letters, two international research groups report on their calculations of what the signature of such a phase transition in a gravitational wave would look like.

- Advertisement -

Quarks, the smallest building-blocks of matter, never appear alone in nature. They are always tightly bound inside the protons and neutrons. However, neutron stars, weighing as much as the Sun, but being just the size of a city like Frankfurt, possess a core so dense that a transition from neutron matter to quark matter may occur. Physicists refer to this process as a phase transition, similar to the liquid-vapor transition in water. In particular, such a phase transition is in principle possible when merging neutron stars form a very massive meta-stable object with densities exceeding that of atomic nuclei and with temperatures 10,000 times higher than in the Sun’s core.

The measurement of gravitational waves emitted by merging neutron stars could serve as a messenger of possible phase transitions in outer space. The phase transition should leave a characteristic signature in the gravitational-wave signal. The research groups from Frankfurt, Darmstadt and Ohio (Goethe University/FIAS/GSI/Kent University) as well as from Darmstadt and Wroclaw (GSI/Wroclaw University) used modern supercomputers to calculate what this signature could look like. For this purpose, they used different theoretical models of the phase transition.

In case a phase transition takes place more after the actual merger, small amounts of quarks will gradually appear throughout the merged object. “With aid of the Einstein equations, we were able to show for the first time that this subtle change in the structure will produce a deviation in the gravitational-wave signal until the newly formed massive neutron star collapses under its own weight to form a black hole,” explains Luciano Rezzolla, who is a professor for theoretical astrophysics at the Goethe University.

In the computer models of Dr. Andreas Bauswein from GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt a phase transition already happens directly after the merger — a core of quark matter forms in the interior of the central object. “We succeeded to show that in this case there will be a distinct shift in the frequency of the gravitational wave signal,” says Bauswein. “Thus, we identified a measurable criterion for a phase transition in gravitational waves of neutron star mergers in the future.”

- Advertisement -

Not all of the details of the gravitational-wave signal are measurable with current detectors yet. However, they will become observable both with the next generation of detectors, as well as with a merger event relatively close to us. A complementary approach to answer the questions about quark matter is offered by two experiments: By colliding heavy ions at the existing HADES setup at GSI and at the future CBM detector at the Facility for Antiproton and Ion Research (FAIR), which is currently under construction at GSI, compressed nuclear matter will be produced. In the collisions, it might be possible to create temperatures and densities that are similar to those in a neutron-star merger. Both methods give new insights into the occurrence of phase transitions in nuclear matter and thus into its fundamental properties.

HELMHOLTZ ASSOCIATION

Header Image – Simulation of merging neutron stars calculated with supercomputers. Different colors show the mass density and the temperature some time after the merger has taken place and shortly before the object collapses to a black hole. Quarks are expected to form where the temperature and density are higher. Credit : C. Breu, L. Rezzolla

- Advertisement -

Stay Updated: Follow us on iOS, Android, Google News, Facebook, Instagram, Twitter, Threads, TikTok, LinkedIn, and our newsletter

spot_img
Mark Milligan
Mark Milligan
Mark Milligan is a multi-award-winning journalist and the Managing Editor at HeritageDaily. His background is in archaeology and computer science, having written over 8,000 articles across several online publications. Mark is a member of the Association of British Science Writers (ABSW), the World Federation of Science Journalists, and in 2023 was the recipient of the British Citizen Award for Education, the BCA Medal of Honour, and the UK Prime Minister's Points of Light Award.
spot_img
spot_img

Mobile Application

spot_img

Related Articles

Ancient inscriptions found on summit of Phu Khat Mountain

Located in Thailand’s Loei Province, Phu Khat stands as the highest peak in the Phu Khat Wildlife Sanctuary, rising to a height of 1,307 metres above sea level.

Giant coin hoard discovered in eastern Poland

A metal detectorist has discovered a significant coin hoard in a field near Zewierszczów, located in Poland’s Lublin Voivodeship.

Archaeologists uncover major Slavic settlement

Excavations for the SuedOstLink infrastructure project have revealed a major Slavic settlement and cemetery west of Nauendorf, Saxony-Anhalt.

Underwater study reveals remarkable details of WWII German U-Boat

An underwater study using 3D photogrammetry has revealed remarkable details of the U-670, a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II.

Intact Roman helmet from First Punic War discovered

Archaeologists have discovered an intact Roman helmet while conducting an underwater study near the Aegadian Islands off Sicily’s western coast.

Ritual tomb discovered in Northern Peru reveals evidence of human sacrifice

Excavations near the Temple of Puémape, an archaeological complex in the San Pedro Lloc district in Peru, have unearthed traces of human sacrifice following the discovery of a ritual tomb.

Archaeologists explore wreck site of revolutionary war gunboat

Archaeologists from the Centre for Maritime Archaeology and Conservation (CMAC) at Texas A&M University have carried out a study of the wreck site of the Philadelphia, a Revolutionary War gunboat.

2,000-year-old Roman bridge found in Aegerten

Archaeologists from the Archaeological Service of the Canton of Bern have uncovered the remains of a 2,000-year-old Roman bridge during excavations near the River Zihl in Aegerten, Switzerland.