### Abstract

Using a new formulation to compute structures of stationary and axisymmetric magnetized barotropic stars in Newtonian gravity, we have succeeded in obtaining numerically exact models of stars with extremely high interior magnetic fields. In this formulation, there appear four arbitrary functions of the magnetic flux function from the integrability conditions among the basic equations. Since in our new formulation these arbitrary functions appear in the expression of the current density, configurations with different current distributions can be specified by choosing the forms of the arbitrary functions. By choosing appropriate forms for the four arbitrary functions, we have solved many kinds of equilibrium configurations both with poloidal and toroidal magnetic fields. Among them, by choosing special form for the toroidal current density, we have been able to obtain magnetized stars which have extremely strong poloidal magnetic fields deep inside the core region near the symmetric axis. By adopting the appropriate model parameters for the neutron stars, the magnetic fields could be 10^{14} ∼ 10^{15} G on the surfaces and be about 10^{17} G in the deep interior regions. For other model parameters appropriate for white dwarfs, the magnetic fields could be around 10^{7} ∼ 10^{8} G (surface regions) and 10^{9} ∼ 10^{10} G (core regions). It is remarkable that the regions with very strong interior magnetic fields are confined to a very narrow region around the symmetric axis in the central part of the stars. The issues of stability of these configurations and of evolutionary paths to reach such configurations need to be investigated in the future work.

Original language | English |
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Title of host publication | Proceedings of the International Astronomical Union |

Pages | 232-235 |

Number of pages | 4 |

Volume | 6 |

Edition | S274 |

DOIs | |

Publication status | Published - 2010 Sep |

Externally published | Yes |

### Publication series

Name | Proceedings of the International Astronomical Union |
---|---|

Number | S274 |

Volume | 6 |

ISSN (Print) | 17439213 |

ISSN (Electronic) | 17439221 |

### Fingerprint

### Keywords

- Stars: interior
- Stars: magnetic fields
- Stars: neutron
- Stars: white dwarfs

### ASJC Scopus subject areas

- Astronomy and Astrophysics

### Cite this

*Proceedings of the International Astronomical Union*(S274 ed., Vol. 6, pp. 232-235). (Proceedings of the International Astronomical Union; Vol. 6, No. S274). https://doi.org/10.1017/S1743921311007009

**Stationary and axisymmetric configurations of compact stars with extremely strong and highly localized magnetic fields.** / Fujisawa, Kotaro; Yoshida, Shin'Ichiro; Eriguchi, Yoshiharu.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Proceedings of the International Astronomical Union.*S274 edn, vol. 6, Proceedings of the International Astronomical Union, no. S274, vol. 6, pp. 232-235. https://doi.org/10.1017/S1743921311007009

}

TY - GEN

T1 - Stationary and axisymmetric configurations of compact stars with extremely strong and highly localized magnetic fields

AU - Fujisawa, Kotaro

AU - Yoshida, Shin'Ichiro

AU - Eriguchi, Yoshiharu

PY - 2010/9

Y1 - 2010/9

N2 - Using a new formulation to compute structures of stationary and axisymmetric magnetized barotropic stars in Newtonian gravity, we have succeeded in obtaining numerically exact models of stars with extremely high interior magnetic fields. In this formulation, there appear four arbitrary functions of the magnetic flux function from the integrability conditions among the basic equations. Since in our new formulation these arbitrary functions appear in the expression of the current density, configurations with different current distributions can be specified by choosing the forms of the arbitrary functions. By choosing appropriate forms for the four arbitrary functions, we have solved many kinds of equilibrium configurations both with poloidal and toroidal magnetic fields. Among them, by choosing special form for the toroidal current density, we have been able to obtain magnetized stars which have extremely strong poloidal magnetic fields deep inside the core region near the symmetric axis. By adopting the appropriate model parameters for the neutron stars, the magnetic fields could be 1014 ∼ 1015 G on the surfaces and be about 1017 G in the deep interior regions. For other model parameters appropriate for white dwarfs, the magnetic fields could be around 107 ∼ 108 G (surface regions) and 109 ∼ 1010 G (core regions). It is remarkable that the regions with very strong interior magnetic fields are confined to a very narrow region around the symmetric axis in the central part of the stars. The issues of stability of these configurations and of evolutionary paths to reach such configurations need to be investigated in the future work.

AB - Using a new formulation to compute structures of stationary and axisymmetric magnetized barotropic stars in Newtonian gravity, we have succeeded in obtaining numerically exact models of stars with extremely high interior magnetic fields. In this formulation, there appear four arbitrary functions of the magnetic flux function from the integrability conditions among the basic equations. Since in our new formulation these arbitrary functions appear in the expression of the current density, configurations with different current distributions can be specified by choosing the forms of the arbitrary functions. By choosing appropriate forms for the four arbitrary functions, we have solved many kinds of equilibrium configurations both with poloidal and toroidal magnetic fields. Among them, by choosing special form for the toroidal current density, we have been able to obtain magnetized stars which have extremely strong poloidal magnetic fields deep inside the core region near the symmetric axis. By adopting the appropriate model parameters for the neutron stars, the magnetic fields could be 1014 ∼ 1015 G on the surfaces and be about 1017 G in the deep interior regions. For other model parameters appropriate for white dwarfs, the magnetic fields could be around 107 ∼ 108 G (surface regions) and 109 ∼ 1010 G (core regions). It is remarkable that the regions with very strong interior magnetic fields are confined to a very narrow region around the symmetric axis in the central part of the stars. The issues of stability of these configurations and of evolutionary paths to reach such configurations need to be investigated in the future work.

KW - Stars: interior

KW - Stars: magnetic fields

KW - Stars: neutron

KW - Stars: white dwarfs

UR - http://www.scopus.com/inward/record.url?scp=79959220160&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79959220160&partnerID=8YFLogxK

U2 - 10.1017/S1743921311007009

DO - 10.1017/S1743921311007009

M3 - Conference contribution

SN - 9780521197410

VL - 6

T3 - Proceedings of the International Astronomical Union

SP - 232

EP - 235

BT - Proceedings of the International Astronomical Union

ER -