Synopsis: Italian Delicacies Served Up in a Neutron Star Crust

A new way of topologically labeling the pasta phases thought to exist in neutron stars could help researchers sort out how the phases contribute to star cooling.
Synopsis figure
C. O. Dorso et al., Phys. Rev. C (2012)

The matter in the outermost layer, or “crust,” of a neutron star (the remnant of a supernova) is believed to host a variety of phases in which dense regions of nucleons are filled with voids of lower density. The presence of the phases, euphemistically referred to as “nuclear pasta” because of their resemblance to the shapes of lasagna, gnocchi, and spaghetti, may affect the emission of neutrinos, the primary mechanism by which the neutron star cools. In Physical Review C, Claudio Dorso of the University of Buenos Aires, Argentina, and colleagues report that a set of topological and geometric descriptors can accurately identify each pasta phase predicted by dynamical simulations, a labeling scheme that could be used to directly map the shape of a pasta phase to its effect on neutrino emission and neutron star cooling.

Dorso et al. classify a particular pasta phase by defining its volume, area, mean curvature, and its Euler characteristic—a number that represents the phase’s topology. Although pasta phases have long been studied theoretically, the authors’ calculations are some of the first to use a classical molecular dynamics model that is consistent with low- to medium-energy nuclear reactions. Moreover, they make no initial assumptions about the phase structure, which should help clarify the balance of forces and parameters that lead to the formation of each phase. – Joseph Kapusta


Features

More Features »

Subject Areas

AstrophysicsNuclear Physics

Previous Synopsis

Atomic and Molecular Physics

Cooling Neutral Atoms in Optical Tweezers

Read More »

Next Synopsis

Chemical Physics

Testing the (Heavier) Waters

Read More »

Related Articles

Synopsis: Off-Axis Jets from Neutron Star Merger
Astrophysics

Synopsis: Off-Axis Jets from Neutron Star Merger

Simulations suggest that the gamma rays accompanying the neutron star merger detected in 2017 came from a short gamma-ray burst viewed at a 30° angle. Read More »

Focus: Laser Bags a Giant Nucleus
Nuclear Physics

Focus: Laser Bags a Giant Nucleus

A laser-based technique provides the most precise measurements to date of nuclear properties for an element above atomic number 100. Read More »

Synopsis: Dark Matter Undetectable in Gravitational Waves
Astrophysics

Synopsis: Dark Matter Undetectable in Gravitational Waves

Calculations show that dark matter affects the propagation of gravitational waves but at a level far below the sensitivity of current detectors. Read More »

More Articles