Effective geometry of a white dwarf

Journal Article · Tue Mar 15 04:00:00 EDT 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.83.064039· OSTI ID:21537559

Bini, D; Cherubini, C; Filippi, S ^[1]

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1. Istituto per le Applicazioni del Calcolo 'M. Picone', CNR, I-00185 Rome (Italy) and ICRA, University of Rome 'La Sapienza', I-00185 Rome (Italy)

The ''effective geometry'' formalism is used to study the perturbations of a white dwarf described as a self-gravitating fermion gas with a completely degenerate relativistic equation of state of barotropic type. The quantum nature of the system causes an absence of homological properties, manifested instead by polytropic stars, and requires a parametric study of the solutions both at the numerical and analytical level. We have explicitly derived a compact analytical parametric approximate solution of Pade type, which gives density curves and stellar radii in good accordance with already existing numerical results. After validation of this new type of approximate solutions, we use them to construct the effective acoustic metric governing general perturbations following Chebsch's formalism. Even in this quantum case, the stellar surface exhibits a curvature singularity due to the vanishing of density, as already evidenced in past studies on nonquantum self-gravitating polytropic stars. The equations of the theory are finally numerically integrated in the simpler case of irrotational spherical pulsating perturbations, including the effect of backreaction, in order to have a dynamical picture of the process occurring in the acoustic metric.

• OSTI ID: 21537559
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 6 Vol. 83; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
79 ASTRONOMY AND ASTROPHYSICS
APPROXIMATIONS
CALCULATION METHODS
CONFIGURATION
DENSITY
DISTURBANCES
DWARF STARS
ENERGY RANGE
EQUATIONS
EQUATIONS OF STATE
FERMIONS
METRICS
PARAMETRIC ANALYSIS
PERTURBATION THEORY
PHYSICAL PROPERTIES
RELATIVISTIC RANGE
SIMULATION
SINGULARITY
SPHERICAL CONFIGURATION
STARS
SURFACES
WHITE DWARF STARS