A Model of the Pulsating Extremely Low-Mass White Dwarf Precursor WASP 0247-25B

Abstract

We present an analysis of the evolutionary and pulsation properties of the extremely low-mass white dwarf precursor (B) component of the double-lined eclipsing system WASP 0247-25. Given that the fundamental parameters of that star have been obtained previously at a unique level of precision, WASP 0247-25B represents the ideal case for testing evolutionary models of this newly-found category of pulsators. Taking into account the known constraints on the mass, orbital period, effective temperature, surface gravity, and atmospheric composition, we present a model that is compatible with these constraints and show pulsation modes that have periods very close to the observed values. Importantly, these modes are predicted excited. Although the overall consistency remains perfectible, the observable properties of WASP 0247-25B are closely reproduced. A key ingredient of our binary evolutionary models is represented by rotational mixing as the main competitor against gravitational settling. Depending on assumptions made about the values of the degree index l for the observed pulsation modes, we found three possible seismic solutions. We discuss two tests, rotational splitting and multicolor photometry, that should readily identify the modes and discriminate between these solutions. However, this will require improved temporal resolution and higher S/N observations than currently available.

arXiv comment9 pages, 5 figures, accepted for publication in the Astrophysical Journal

References in corpus (27)

• The chemical composition of the Sun
• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
• Evolutionary and pulsational properties of white dwarf stars
• Pulsating White Dwarf Stars and Precision Asteroseismology
• New evolutionary sequences for extremely low mass white dwarfs: Homogeneous mass and age determinations, and asteroseismic prospects
• Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing
• Diffusion and the occurrence of hydrogen shell flashes in helium white dwarf stars
• EL CVn-type binaries - Discovery of 17 helium white dwarf precursors in bright eclipsing binary star systems
• Multi-periodic pulsations of a stripped red giant star in an eclipsing binary
• The timescale of low-mass proto-helium white dwarf evolution
• A Metal-Rich Low-Gravity Companion to a Massive Millisecond Pulsar
• Precise Atmospheric Parameters for the Shortest Period Binary White Dwarfs: Gravitational Waves, Metals, and Pulsations
• The ELM Survey. VI. Eleven New Double Degenerates
• WASP 1628+10 - an EL CVn-type binary with a very-low-mass stripped-red-giant star and multi-periodic pulsations
• The Potential of Multi-Colour Photometry for Pulsating Subdwarf B Stars
• Pulsations in Hydrogen Burning Low Mass Helium White Dwarfs
• The seismic properties of low-mass He-core white dwarf stars
• Pulsating low-mass white dwarfs in the frame of new evolutionary sequences: III. The pre-ELM white dwarf instability strip
• Discovery of Three Pulsating, Mixed-atmosphere, Extremely Low-mass White Dwarf Precursors
• The Physical Nature of Subdwarf A Stars: White Dwarf Impostors
• SDSS J074511.56+194926.5: Discovery of a Metal-Rich and Tidally Distorted Extremely Low Mass White Dwarf
• Heavy metals in a light white dwarf: Abundances of the metal-rich, extremely low-mass GALEX J1717+6757
• Asteroseismic test of rotational mixing in low-mass white dwarfs
• Two new pulsating low-mass pre-white dwarfs or SX Phenix stars?*
• Quantitative spectral analysis of the sdB star HD 188112: a helium-core white dwarf progenitor

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• The McDonald Observatory search for pulsating sdA stars: asteroseismic support for multiple populations
• Pulsation and Rotation of the EL CVn-type Eclipsing Binary 1SWASP J024743.37-251549.2