# Extreme neutron stars from Extended Theories of Gravity

## Abstract

We discuss neutron stars with strong magnetic mean fields in the framework of Extended Theories of Gravity. In particular, we take into account models derived from f(R) and f(G) extensions of General Relativity where functions of the Ricci curvature invariant R and the Gauss-Bonnet invariant G are respectively considered. Dense matter in magnetic mean field, generated by magnetic properties of particles, is described by assuming a model with three meson fields and baryons octet. As result, the considerable increasing of maximal mass of neutron stars can be achieved by cubic corrections in f(R) gravity. In principle, massive stars with M > 4M{sub ☉} can be obtained. On the other hand, stable stars with high strangeness fraction (with central densities ρ{sub c} ∼ 1.5–2.0 GeV/fm{sup 3}) are possible considering quadratic corrections of f(G) gravity. The magnetic field strength in the star center is of order 6–8 × 10{sup 18} G. In general, we can say that other branches of massive neutron stars are possible considering the extra pressure contributions coming from gravity extensions. Such a feature can constitute both a probe for alternative theories and a way out to address anomalous self-gravitating compact systems.

- Authors:

- I. Kant Baltic Federal University, Institute of Physics and Technology, Nevskogo st. 14, Kaliningrad, 236041 (Russian Federation)
- Dipartimento di Fisica, Università di Napoli ''Federico II'', Via Cinthia, 9, Napoli, I-80126 Italy (Italy)
- Instituciò Catalana de Recerca i Estudis Avançats (ICREA), Barcelona (Spain)

- Publication Date:

- OSTI Identifier:
- 22382039

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 01; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BARYON OCTETS; CORRECTIONS; GENERAL RELATIVITY THEORY; GEV RANGE; GRAVITATION; MAGNETIC PROPERTIES; MEAN-FIELD THEORY; MESONS; NEUTRON STARS

### Citation Formats

```
Astashenok, Artyom V., Capozziello, Salvatore, and Odintsov, Sergei D., E-mail: artyom.art@gmail.com, E-mail: capozziello@na.infn.it, E-mail: odintsov@ieec.uab.es.
```*Extreme neutron stars from Extended Theories of Gravity*. United States: N. p., 2015.
Web. doi:10.1088/1475-7516/2015/01/001.

```
Astashenok, Artyom V., Capozziello, Salvatore, & Odintsov, Sergei D., E-mail: artyom.art@gmail.com, E-mail: capozziello@na.infn.it, E-mail: odintsov@ieec.uab.es.
```*Extreme neutron stars from Extended Theories of Gravity*. United States. doi:10.1088/1475-7516/2015/01/001.

```
Astashenok, Artyom V., Capozziello, Salvatore, and Odintsov, Sergei D., E-mail: artyom.art@gmail.com, E-mail: capozziello@na.infn.it, E-mail: odintsov@ieec.uab.es. Thu .
"Extreme neutron stars from Extended Theories of Gravity". United States.
doi:10.1088/1475-7516/2015/01/001.
```

```
@article{osti_22382039,
```

title = {Extreme neutron stars from Extended Theories of Gravity},

author = {Astashenok, Artyom V. and Capozziello, Salvatore and Odintsov, Sergei D., E-mail: artyom.art@gmail.com, E-mail: capozziello@na.infn.it, E-mail: odintsov@ieec.uab.es},

abstractNote = {We discuss neutron stars with strong magnetic mean fields in the framework of Extended Theories of Gravity. In particular, we take into account models derived from f(R) and f(G) extensions of General Relativity where functions of the Ricci curvature invariant R and the Gauss-Bonnet invariant G are respectively considered. Dense matter in magnetic mean field, generated by magnetic properties of particles, is described by assuming a model with three meson fields and baryons octet. As result, the considerable increasing of maximal mass of neutron stars can be achieved by cubic corrections in f(R) gravity. In principle, massive stars with M > 4M{sub ☉} can be obtained. On the other hand, stable stars with high strangeness fraction (with central densities ρ{sub c} ∼ 1.5–2.0 GeV/fm{sup 3}) are possible considering quadratic corrections of f(G) gravity. The magnetic field strength in the star center is of order 6–8 × 10{sup 18} G. In general, we can say that other branches of massive neutron stars are possible considering the extra pressure contributions coming from gravity extensions. Such a feature can constitute both a probe for alternative theories and a way out to address anomalous self-gravitating compact systems.},

doi = {10.1088/1475-7516/2015/01/001},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 01,

volume = 2015,

place = {United States},

year = {Thu Jan 01 00:00:00 EST 2015},

month = {Thu Jan 01 00:00:00 EST 2015}

}