Crust Composition and the Shallow Heat Source in KS 1731–260
The presence of a strong shallow heat source of unknown origin in accreting neutron star crusts has been inferred by analyzing x-ray observations of their cooling in quiescence. We model the cooling of KS 1731-260 using realistic crust compositions and nuclear heating and cooling sources from detailed nuclear reaction network calculations. We find that the required strength of the shallow heat source in KS 1731-260 is reduced by more than a factor of 3 compared to previous analysis, a 5σ difference that alleviates the need for exotic solutions. Our analysis also suggests the existence of an impure nuclear pasta layer in the inner crust of KS 1731-260, though future observations will provide more stringent constraints. In addition, we obtain constraints on the dominant surface burning modes of KS 1731-260 over its history.
Authors
- James B. Grace (ORCID: https://orcid.org/0000-0001-6374-4726)
- A. V. Afanasjev (ORCID: https://orcid.org/0000-0002-4220-2386)
- L. R. Gasques (ORCID: https://orcid.org/0000-0002-0963-1816)
- R. Jain (ORCID: https://orcid.org/0000-0001-9859-1512)
- R. Lau (ORCID: https://orcid.org/0000-0001-9263-0349)
- Alexander Heger (ORCID: https://orcid.org/0000-0002-3684-1325)
- H. Schatz (ORCID: https://orcid.org/0000-0003-1674-4859)
- M. Beard
- Edward F. Brown (ORCID: https://orcid.org/0000-0003-3806-5339)
- G. W. Hitt (ORCID: https://orcid.org/0000-0003-3161-3283)
- Y. Xu (ORCID: https://orcid.org/0000-0003-1688-1554)
- M. Wiescher (ORCID: https://orcid.org/0000-0002-3409-3319)
- W.-J. Ong (ORCID: https://orcid.org/0000-0002-0945-8654)
- W. R. Hix (ORCID: https://orcid.org/0000-0002-9481-9126)
Institutions
- University of Notre Dame (US)
- Lawrence Livermore National Laboratory (US)
- Oak Ridge National Laboratory (US)
- Universidade de São Paulo (BR)
- Coastal Carolina University (US)
- Australian Regenerative Medicine Institute (AU)
- Stanly Community College (US)
- Knoxville College (US)
- Horia Hulubei National Institute for R and D in Physics and Nuclear Engineering (RO)
- Astronomy Australia (AU)
- Facility for Rare Isotope Beams
- Monash University (AU)
- University of Tennessee at Knoxville (US)
- Michigan State University (US)
- University of Hong Kong (HK)
- Mississippi State University (US)
Publication Details
- Journal
- Physical Review Letters
- Published
- 2025-09-18
- DOI
- https://doi.org/10.1103/jwc8-xfhv
- Citations
- 1
- Primary Topic
- Pulsars and Gravitational Waves Research
- Type
- article
- Field-Weighted Citation Impact
- 1.15