Hydrogen‐accreting Carbon‐Oxygen White Dwarfs

Cassisi, S.; Iben, Icko; Tornambé, Amedeo

doi:10.1086/305381

Cited by 100 publications

(120 citation statements)

References 47 publications

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“…Fortunately, although it is not clear how the WD adjusts to alternating helium flashes and stable hydrogen shell burning in the OTW model, this issue probably does not arise in the CEW model. In addition, ηHe could be larger than derived by Kato & Hachisu (2004) if the effect of H shell burning has been accounted for, since the nuclear energy produced via H-burning keeps the underlying He buffer hotter, resulting in weaker and more frequent He flashes (Cassisi et al 1998). Especially, Hillman et al (2016) recently found that, although a significant fraction of the material accumulated prior to the flash is lost during the first few helium shell flashes, the fraction decreases with repeated helium shell flashes and eventually no mass is lost at all during subsequent flashes.…”

Section: The Differences Between the Cew Model And The Otw Modelmentioning

confidence: 94%

A common-envelope wind model for Type Ia supernovae – I. Binary evolution and birth rate

Meng

Podsiadlowski

2017

Monthly Notices of the Royal Astronomical Society

120

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The single-degenerate (SD) model is one of the principal models for the progenitors of type Ia supernovae (SNe Ia), but some of the predictions in the most widely studied version of the SD model, i.e. the optically thick wind (OTW) model, have not been confirmed by observations. Here, we propose a new version of the SD model in which a common envelope (CE) is assumed to form when the mass-transfer rate between a carbon-oxygen white dwarf (CO WD) and its companion exceeds a critical accretion rate. The WD may gradually increase its mass at the base of the CE. Due to the large nuclear luminosity for stable hydrogen burning, the CE may expand to giant dimensions and will lose mass from the surface of the CE by a CE wind (CEW). Because of the low CE density, the binary system will avoid a fast spiral-in phase and finally re-emerge from the CE phase. Our model may share the virtues of the OTW model but avoid some of its shortcomings. We performed binary stellar evolution calculations for more than 1100 close WD + MS binaries. Compared with the OTW model, the parameter space for SNe Ia from our CEW model extends to more massive companions and less massive WDs. Correspondingly, the Galactic birth rate from the CEW model is higher than that from the OTW model by ∼30%. Finally, we discuss the uncertainties of the CEW model and the differences between our CEW model and the OTW model.

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Section: The Differences Between the Cew Model And The Otw Modelmentioning

confidence: 94%

A common-envelope wind model for Type Ia supernovae – I. Binary evolution and birth rate

Meng

Podsiadlowski

2017

Monthly Notices of the Royal Astronomical Society

120

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“…The rationale of even considering an accretion rate |Ṁ 2 | >Ṁ Edd,WD is that the WD may drive a strong wind in a bipolar outflow which may prevent the WD envelope from otherwise expanding into giant star dimensions (Nomoto et al 1979b). Many previous studies of accreting WDs have adapted the optically thick wind model of Kato & Iben (1992) and Kato & Hachisu (1994), without any restrictions on |Ṁ 2 | (see Cassisi et al 1998;Langer et al 2000, for a critique of this assumption). Given the uncertainties regarding the validity of this model, we adopt a maximum allowed mass-transfer rate limit of |Ṁ 2 | =Ṁ CE = 3Ṁ Edd,WD .…”

Section: Dependence On Mass-transfer Ratesmentioning

confidence: 99%

Evolution towards and beyond accretion-induced collapse of massive white dwarfs and formation of millisecond pulsars

Tauris

Sanyal

Yoon

et al. 2013

A&A

147

181

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Context. Millisecond pulsars (MSPs) are generally believed to be old neutron stars (NSs), formed via type Ib/c core-collapse supernovae (SNe), which have been spun up to high rotation rates via accretion from a companion star in a low-mass X-ray binary (LMXB). In an alternative formation channel, NSs are produced via the accretion-induced collapse (AIC) of a massive white dwarf (WD) in a close binary. Aims. Here we investigate binary evolution leading to AIC and examine if NSs formed in this way can subsequently be recycled to form MSPs and, if so, how they can observationally be distinguished from pulsars formed via the standard core-collapse SN channel in terms of their masses, spins, orbital periods and space velocities. Methods. Numerical calculations with a detailed stellar evolution code were used for the first time to study the combined pre-and post-AIC evolution of close binaries. We investigated the mass transfer onto a massive WD (treated as a point mass) in 240 systems with three different types of non-degenerate donor stars: main-sequence stars, red giants, and helium stars. When the WD is able to accrete sufficient mass (depending on the mass-transfer rate and the duration of the accretion phase) we assumed it collapses to form a NS and we studied the dynamical effects of this implosion on the binary orbit. Subsequently, we followed the mass-transfer epoch which resumes once the donor star refills its Roche lobe and calculated the continued LMXB evolution until the end. Results. We show that recycled pulsars may form via AIC from all three types of progenitor systems investigated and find that the final properties of the resulting MSPs are, in general, remarkably similar to those of MSPs formed via the standard core-collapse SN channel. However, as a consequence of the fine-tuned mass-transfer rate necessary to make the WD grow in mass, the resultant MSPs created via the AIC channel preferentially form in certain orbital period intervals. In addition, their predicted small space velocities can also be used to identify them observationally. The production time of NSs formed via AIC can exceed 10 Gyr which can therefore explain the existence of relatively young NSs in globular clusters. Our calculations are also applicable to progenitor binaries of SNe Ia under certain conditions.

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“…Iben 1982;Nomoto 1982;Fujimoto & Sugimoto 1982;Saio & Nomoto 1985Kawai et al 1988;Cassisi et al 1998;Piersanti et al 2000;Langer et al 2002), little attention has so far been devoted to the effects of angular momentum accretion and the ensuing white dwarf rotation (see Sect. 3.1).…”

Section: Introductionmentioning

confidence: 99%

Presupernova evolution of accreting white dwarfs with rotation

Yoon

Langer

2004

A&A

149

190

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Abstract. We discuss the effects of rotation on the evolution of accreting carbon-oxygen white dwarfs, with the emphasis on possible consequences in Type Ia supernova (SN Ia) progenitors. Starting with a slowly rotating white dwarf, we consider the accretion of matter and angular momentum from a quasi-Keplerian accretion disk. Numerical simulations with initial white dwarf masses of 0.8, 0.9 and 1.0 M and accretion of carbon-oxygen rich matter at rates of 3 . . . 10 × 10 −7 M /yr are performed. The models are evolved either up to a ratio of rotational to potential energy of T/W = 0.18 -as angular momentum loss through gravitational wave radiation will become important for T/W < 0.18 -or to central carbon ignition. The role of the various rotationally induced hydrodynamic instabilities for the transport of angular momentum inside the white dwarf is investigated. We find that the dynamical shear instability is the most important one in the highly degenerate core, while Eddington-Sweet circulations, Goldreich-Schubert-Fricke instability and secular shear instability are most relevant in the nondegenerate envelope. Our results imply that accreting white dwarfs rotate differentially throughout, with a shear rate close to the threshold value for the onset of the dynamical shear instability. As the latter depends on the temperature of the white dwarf, the thermal evolution of the white dwarf core is found to be relevant for the angular momentum redistribution. As found previously, significant rotation is shown to lead to carbon ignition masses well above 1.4 M . Our models suggest a wide range of white dwarf explosion masses, which could be responsible for some aspects of the diversity observed in SNe Ia. We analyze the potential role of the bar-mode and the r-mode instability in rapidly rotating white dwarfs, which may impose angular momentum loss by gravitational wave radiation. We discuss the consequences of the resulting spin-down for the fate of the white dwarf, and the possibility to detect the emitted gravitational waves at frequencies of 0.1 . . . 1.0 Hz in nearby galaxies with LISA. Possible implications of fast and differentially rotating white dwarf cores for the flame propagation in exploding white dwarfs are also briefly discussed.

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Hydrogen‐accreting Carbon‐Oxygen White Dwarfs

Cited by 100 publications

References 47 publications

A common-envelope wind model for Type Ia supernovae – I. Binary evolution and birth rate

A common-envelope wind model for Type Ia supernovae – I. Binary evolution and birth rate

Evolution towards and beyond accretion-induced collapse of massive white dwarfs and formation of millisecond pulsars

Presupernova evolution of accreting white dwarfs with rotation

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