Strongly magnetized cold electron degenerate gas: Mass-radius relation of the magnetized white dwarf

Abstract

We consider a relativistic, degenerate electron gas at zero-temperature under the influence of a strong, uniform, static magnetic field, neglecting any form of interactions. Since the density of states for the electrons changes due to the presence of the magnetic field (which gives rise to Landau quantization), the corresponding equation of state also gets modified. In order to investigate the effect of very strong magnetic field, we focus only on systems in which a maximum of either one, two or three Landau level(s) is/are occupied. This is important since, if a very large number of Landau levels are filled, it implies a very low magnetic field strength which yields back Chandrasekhar's celebrated non-magnetic results. The maximum number of occupied Landau levels is fixed by the correct choice of two parameters, namely the magnetic field strength and the maximum Fermi energy of the system. We study the equations of state of these one-level, two-level and three-level systems and compare them by taking three different maximum Fermi energies. We also find the effect of the strong magnetic field on the mass-radius relation of the underlying star composed of the gas stated above. We obtain an exciting result that, it is possible to have an electron degenerate static star, namely magnetized white dwarfs, with a mass significantly greater than the Chandrasekhar limit in the range 2.3-2.6M_Sun, provided it has an appropriate magnetic field strength and central density. In fact, recent observations of peculiar Type Ia supernovae - SN 2006gz, SN 2007if, SN 2009dc, SN 2003fg - seem to suggest super-Chandrasekhar-mass white dwarfs with masses up to 2.4-2.8M_Sun, as their most likely progenitors. Interestingly our results seem to lie within the observational limits.

28 pages including 7 figures; section 4.1 significantly modified, section 4.7 and Appendix including Figure 7 added; version appear to Physical Review D

References in corpus (4)

• The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star
• Equation of State of a Dense and Magnetized Fermion System
• Mass of highly magnetized white dwarfs exceeding the Chandrasekhar limit: An analytical view
• Violation of Chandrasekhar Mass Limit: The Exciting Potential of Strongly Magnetized White Dwarfs

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• GRMHD formulation of highly super-Chandrasekhar magnetized white dwarfs: stable configurations of non-spherical white dwarfs
• Violation of Chandrasekhar Mass Limit: The Exciting Potential of Strongly Magnetized White Dwarfs
• One possible solution of peculiar type Ia supernovae explosions caused by a charged white dwarf
• Mass-radius relation of strongly magnetized white dwarfs: nearly independent of Landau quantization
• Revised density of magnetized nuclear matter at the neutron drip line
• Quark matter with strong magnetic field and possibility of the third family of compact stars
• Comments on "Strongly magnetized cold degenerate electron gas: Mass-radius relation of the magnetized white dwarf"