Nuclear Astrophysics

It is a really exciting time for Nuclear Astrophysics, with:

  • New space and ground-based observations are providing new insights into the Cosmos,
  • Advances in computation and technology allow advanced 3D stellar models,
  • New opportunities for experimental and theoretical nuclear physics.

To fully exploit the progress in astrophysics our experimental and theoretical programmes focus on the origin of the chemical elements throughout the Life and Death of Massive Stars, as well as the impact of nuclear physics in the extreme astrophysical environments of Compact Objects and Binaries.

In our programme on the Life and Death of Massive Stars, we seek to answer two key questions:- What role do massive stars play in the Galaxy?- What is the impact of core collapse supernovae on galactic chemical evolution?

To tackle these questions we focus on the following strands of research:‌

  1. We will improve our understanding of carbon production and destruction during fusion of helium and carbon in stars;This programme includes studies of cluster dynamics and it’s impact on astrophysical processes with experiments at JYFL, Köln, and Orsay. The programme has recently expanded to include the new Andromeda facility at Orsay, and through a new Memorandum of Understanding between University of York and the Extreme Light Infrastructure - Nuclear Physics facility currently under construction in Bucharest, Romania. Our work at this facility will lead the way for direct gamma-induced studies of astrophysical reactions at what will become the world-leading gamma-beam facility.
  2. We study radioisotope synthesis in massive stars and CCSN (e.g. 26Al and 44Ti);We study key reactions that drive the production of radioisotopes, 
    ‌such as the radioactive 26Al and 44Ti, both of which have recently been observed through space-based gamma-ray telescopes. Our programme for studies of 26Al includes two recent papers in Physical Review Letters: York scientists unlock secrets of stars through aluminium, with planned experiments using the TUDA and SHARC detector facilities at the TRIUMF laboratory in Vancouver, Canada.

 

 

The photos found above show the SHARC silicon detector array at TRIUMF (left), and a representation of one model (linear chain) for the 12C Hoyle state (right)


‌Our work on Compact Objects and Binaries, is similarly focussed on the two key questions:- How do compact binaries contribute to the production of heavy elements?- How does the nuclear equation of state drive the structure and dynamics of neutron stars and neutron-star mergers?

 

To tackle those key questions identified in this area, we are working on a microscopic description of the evolution of neutron-star binary systems and neutron-star mergers. This includes treatment of the high temperatures involved in these scenarios. We further investigate heavy-element production during x-ray bursts and thermonuclear supernovae and mergers.

 

[Photo credits: CXC/M. Weiss]