Physics of Particles and Nuclei Letters

, Volume 13, Issue 4, pp 442–450 | Cite as

Constraints on the central density and chemical composition of the white dwarf RX J0648.0-4418 with a record period of rotation in a model with the equation of state of an ideal degenerate electron gas

Physics of Elementary Particles and Atomic Nuclei. Theory

Abstract

A system of equations and inequalities that allows one to determine the constraints on central density ρ c and the chemical composition, which is governed by parameter μ e , of the white dwarf RX J0648.0- 4418 with a record short period of rotation T = 13.18s and mass m = (1.28 ± 0.05)m⊙, has been derived. The analysis of numerical solutions of this system reveal a complex dependence of μ e on ρ c . The intervals of variation of μ e and ρ c are as follows: 1.09 ≤ μ e ≤ 1.21 and 9.04 ≤ μ e 0 ≤ 1030 = 0.98 × 106 g/cm3). This range of μ e values suggests that the white dwarf RX J0648.0-4418 is not made of pure hydrogen and should contain 9–21% of heavy elements. Calculations have been performed with the equation of state of an ideal degenerate electron gas. Approximate analytic expressions (with an accuracy of 10-3) for the minimum period T min and mass m of the white dwarf are obtained. It is demonstrated that the white-dwarf mass is almost doubled (compared to the case of no rotation at a fixed central density) as period T approaches T min.

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© Pleiades Publishing, Ltd. 2016

Authors and Affiliations

  1. 1.Tver State UniversityTverRussia

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