https://doi.org/10.1140/epja/s10050-025-01594-6
Regular Article - Theoretical Physics
Filling fractions for the formation of nuclear pasta in neutron stars: semiclassical vs liquid-drop predictions
1
Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, CP226, 1050, Brussels, Belgium
2
Ioffe Institute, Politeknicheskaya 26, 194021, Saint Petersburg, Russia
Received:
25
March
2025
Accepted:
11
May
2025
Published online:
10
June
2025
Historically, a sequence of nuclear pasta shapes was predicted to appear in the deepest region of the inner crust of a neutron star within the compressible liquid-drop picture, when the filling fraction u exceeds some threshold values. However, later calculations showed that these values depend on the details of the liquid-drop model. Here we investigate the existence of pasta in neutron stars within the semiclassical extended Thomas-Fermi approach using various generalized Skyrme functionals. The filling fractions for the different transitions are found to be quasi-universal, unlike the pasta density ranges governed by the symmetry energy at relevant densities. In particular, pasta emerge at 
. By applying a simplified stability criterion within the liquid-drop framework, we show that these values of 
can be explained by the nuclear curvature correction. In this way, the abundance of pasta can be easily estimated. This criterion can also be used to optimize the search of pasta within the more realistic extended Thomas-Fermi approach.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
