scholarly journals Structure of a massive common envelope in the common-envelope wind model for Type Ia supernovae

2020 ◽  
Vol 633 ◽  
pp. A41
Author(s):  
Ren Song ◽  
Xiangcun Meng ◽  
Philipp Podsiadlowski ◽  
Yingzhen Cui
Keyword(s):  
Asymptotic Giant Branch ◽  
Dominant Factor ◽  
Lower Envelope ◽  
Type Ia Supernovae ◽  
Mixing Length ◽  
Common Envelope ◽  
Heating Source ◽  
Type Ia ◽  
The Common ◽  
Ia Supernovae

Context. Although Type Ia supernovae (SNe Ia) are important in many astrophysical fields, the nature of their progenitors is still unclear. A new version of the single-degenerate model has been developed recently, the common-envelope wind (CEW) model, in which the binary is enshrouded in a common envelope (CE) during the main accretion phase. This model is still in development and has a number of open issues, for example what is the exact appearance of such a system during the CE phase? Aims. In this paper we investigate this question for a system with a massive CE. Methods. We use a thermally pulsing asymptotic giant branch (TPAGB) star with a CO core of 0.976 M⊙ and an envelope of 0.6 M⊙ to represent the binary system. The effects of the companion’s gravity and the rotation of the CE are mimicked by modifying the gravitational constant. The energy input from the friction between the binary and the CE is taken into account by an extra heating source. Results. For a thick envelope, the modified TPAGB star looks similar to a canonical TPAGB star but with a smaller radius, a higher effective temperature, and a higher surface luminosity. This is primarily caused by the effect of the companion’s gravity, which is the dominant factor in changing the envelope structure. The mixing length at the position of the companion can be larger than the local radius, implying a breakdown of mixing-length theory and suggesting the need for more turbulence in this region. The modified TPAGB star is more stable than the canonical TPAGB star and the CE density around the companion is significantly higher than that assumed in the original CEW model. Conclusions. Future work will require the modelling of systems with lower envelope masses and the inclusion of hydrodynamical effects during the CE phase.

The common-envelope wind model for type Ia supernovae

2018 ◽  
Vol 14 (S343) ◽  
pp. 470-471
Author(s):  
Xiangcun Meng ◽  
Philipp. Podsiadlowski
Keyword(s):  
Transfer Rate ◽  
Accretion Rate ◽  
Mass Transfer Rate ◽  
Type Ia Supernovae ◽  
Wind Model ◽  
Common Envelope ◽  
Type Ia ◽  
The Common ◽  
Ia Supernovae ◽  
Hybrid Carbon

AbstractWe have developed a new version of the SD model for type Ia supernovae (SNe Ia) in which a common envelope (CE) is assumed to form if the mass-transfer rate between a carbon/oxygen white dwarf (CO WD) and its companion exceeds a critical accretion rate. Based on this model, we found that both SN 2002cx-like and SN Ia-CSM objects may share a similar origin, i.e. these peculiar objects may originate from the explosion of hybrid carbon/oxygen/neon white dwarfs (CONe WDs) in SD systems, where SNe Ia-CSM explode in systems with a massive CE of ∼1 M⊙, while SN 2002cx-like events correspond to events without a massive CE.

scholarly journals The Core-Degenerate Scenario for Type Ia Supernovae

2011 ◽  
Vol 7 (S281) ◽  
pp. 72-75 ◽  
Author(s):  
Noam Soker
Keyword(s):  
Critical Mass ◽  
Asymptotic Giant Branch ◽  
Type Ia Supernovae ◽  
Star Forming ◽  
The Core ◽  
Stellar Formation ◽  
Merger Process ◽  
Type Ia ◽  
The Common ◽  
Ia Supernovae

AbstractIn the core-degenerate (CD) scenario for the formation of Type Ia supernovae (SNe Ia) the Chandrasekhar or super-Chandrasekhar mass white dwarf (WD) is formed at the termination of the common envelope phase or during the planetary nebula phase, from a merger of a WD companion with the hot core of a massive asymptotic giant branch (AGB) star. The WD is destroyed and accreted onto the more massive core. In the CD scenario the rapidly rotating WD is formed shortly after the stellar formation episode, and the delay from stellar formation to explosion is basically determined by the spin-down time of the rapidly rotating merger remnant. The spin-down is due to the magneto-dipole radiation torque. Several properties of the CD scenario make it attractive compared with the double-degenerate (DD) scenario. (1) Off-center ignition of carbon during the merger process is not likely to occur. (2) No large envelope is formed. Hence avoiding too much mass loss that might bring the merger remnant below the critical mass. (3) This model explains the finding that more luminous SNe Ia occur preferentially in star forming galaxies.

scholarly journals Type Ia Supernovae and the Uncertainties in their Progenitor Evolution

2011 ◽  
Vol 7 (S281) ◽  
pp. 236-239
Author(s):  
J. S. W. Claeys ◽  
O. R. Pols ◽  
R. G. Izzard
Keyword(s):  
Type Ia Supernovae ◽  
Population Synthesis ◽  
Common Envelope ◽  
Type Ia ◽  
The Common ◽  
Ia Supernovae

AbstractWe use binary population synthesis to study the main proposed channels leading to Type Ia supernovae, the single degenerate channel (SD) and double degenerate channel (DD). For this purpose, we discuss the progenitor evolution and the influence of the common envelope efficiency, αce, on the rate of the different channels. Our study demonstrates the large αce-dependence of both channels, especially for the SD channel.

scholarly journals Convection and spin-up during common envelope evolution: the formation of short-period double white dwarfs

2020 ◽  
Vol 497 (2) ◽  
pp. 1895-1903 ◽  
Author(s):  
E C Wilson ◽  
J Nordhaus
Keyword(s):  
Stellar Evolution ◽  
White Dwarfs ◽  
Orbital Parameter ◽  
Type Ia Supernovae ◽  
Core Mass ◽  
Common Envelope ◽  
Short Period ◽  
Type Ia ◽  
Ia Supernovae ◽  
Progenitor Stars

ABSTRACT The formation channels and predicted populations of double white dwarfs (DWDs) are important because a subset will evolve to be gravitational-wave sources and/or progenitors of Type Ia supernovae. Given the observed population of short-period DWDs, we calculate the outcomes of common envelope (CE) evolution when convective effects are included. For each observed white dwarf (WD) in a DWD system, we identify all progenitor stars with an equivalent proto-WD core mass from a comprehensive suite of stellar evolution models. With the second observed WD as the companion, we calculate the conditions under which convection can accommodate the energy released as the orbit decays, including (if necessary) how much the envelope must spin-up during the CE phase. The predicted post-CE final separations closely track the observed DWD orbital parameter space, further strengthening the view that convection is a key ingredient in CE evolution.

scholarly journals Properties of the post-inspiral common envelope ejecta – I. Dynamical and thermal evolution

2019 ◽  
Vol 489 (3) ◽  
pp. 3334-3350 ◽  
Author(s):  
Roberto Iaconi ◽  
Keiichi Maeda ◽  
Orsola De Marco ◽  
Takaya Nozawa ◽  
Thomas Reichardt
Keyword(s):  
Thermal Evolution ◽  
Kinematic Model ◽  
Numerical Approach ◽  
Binary Interaction ◽  
Recombination Energy ◽  
Compact Binaries ◽  
Common Envelope ◽  
Type Ia ◽  
The Common ◽  
Ia Supernovae

ABSTRACT We investigate the common envelope binary interaction, that leads to the formation of compact binaries, such as the progenitors of Type Ia supernovae or of mergers that emit detectable gravitational waves. In this work, we diverge from the classic numerical approach that models the dynamic inspiral. We focus instead on the asymptotic behaviour of the common envelope expansion after the dynamic inspiral terminates. We use the SPH code phantom to simulate one of the set-ups from Passy et al., with a 0.88 M⊙, 83 R⊙ RGB primary and a 0.6 M⊙ companion, then we follow the ejecta expansion for 50 yr. Additionally, we utilize a tabulated equation of state including the envelope recombination energy in the simulation (Reichardt et al.), achieving a full unbinding. We show that, as time passes, the envelope’s radial velocities dominate over the tangential ones, hence allowing us to apply an homologous expansion kinematic model to the ejecta. The external layers of the envelope become homologous as soon as they are ejected, but it takes 5000 d (14 yr) for the bulk of the unbound gas to achieve the homologously expanding regime. We observe that the complex distribution generated by the dynamic inspiral evolves into a more ordered, shell-like shaped one in the asymptotic regime. We show that the thermodynamics of the expanding envelope are in very good agreement with those expected for an adiabatically expanding sphere under the homologous condition and give a prediction for the location and temperature of the photosphere assuming dust to be the main source of opacity. This technique ploughs the way to determining the long-term light behaviour of common envelope transients.

scholarly journals Common envelope to explosion delay time of Type Ia supernovae

2019 ◽  
Vol 490 (2) ◽  
pp. 2430-2435 ◽  
Author(s):  
Noam Soker
Keyword(s):  
Delay Time ◽  
Planetary Nebula ◽  
Time Distribution ◽  
Circumstellar Matter ◽  
Type Ia Supernovae ◽  
Common Envelope ◽  
Type Ia ◽  
Explosion Delay ◽  
Ia Supernovae ◽  
Short Times

ABSTRACT I study the rate of Type Ia supernovae (SNe Ia) within about a million years after the assumed common envelope evolution (CEE) that forms the progenitors of these SNe Ia, and find that the population of SNe Ia with short CEE to explosion delay (CEED) time is ≈few × 0.1 of all SNe Ia. I also claim for an expression for the rate of these SNe Ia that occur at short times after the CEE ($t_{\rm CEED} \lesssim 10^6 {~\rm yr}$), which is different from that of the delay time distribution (DTD) billions of years after star formation. This tentatively hints that the physical processes that determine the short CEED time distribution (CEEDTD) are different (at least to some extent) from those that determine the DTD at billions of years. To reach these conclusions I examine SNe Ia that interact with a circumstellar matter (CSM) within months after explosion, so-called SNe Ia-CSM, and the rate of SNe Ia that on a time-scale of tens to hundreds of years interact with a CSM that might have been a planetary nebula, so-called SNe Ia inside a planetary nebula (SNIPs). I assume that the CSM in these populations results from a CEE, and hence this study is relevant mainly to the core-degenerate (CD) scenario, the double-degenerate (DD) scenario, the double-detonation (DDet) scenario with white dwarf companions, and to the CEE-wind channel of the single-degenerate (SD) scenario.

WD+AGB star systems as the progenitors of type Ia supernovae

2018 ◽  
Vol 14 (S343) ◽  
pp. 540-541
Author(s):  
Bo Wang
Keyword(s):  
Type Ia Supernovae ◽  
Population Synthesis ◽  
Final Phase ◽  
Common Envelope ◽  
The Core ◽  
Delay Times ◽  
Careful Treatment ◽  
Type Ia ◽  
Ia Supernovae ◽  
Synthesis Approach

AbstractWD+AGB star systems have been suggested as an alternative way for producing type Ia supernovae (SNe Ia), known as the core-degenerate (CD) scenario. In the CD scenario, SNe Ia are produced at the final phase during the evolution of common-envelope through a merger between a carbon-oxygen (CO) WD and the CO core of an AGB secondary. However, the rates of SNe Ia from this scenario are still uncertain. In this work, I carried out a detailed investigation on the CD scenario based on a binary population synthesis approach. I found that the Galactic rates of SNe Ia from this scenario are not more than 20% of total SNe Ia due to more careful treatment of mass transfer, and that their delay times are in the range of ∼90 − 2500 Myr, mainly contributing to the observed SNe Ia with short and intermediate delay times.

scholarly journals Population Synthesis of Type Ia SNe: Constraining Free Parameters from Observations

2011 ◽  
Vol 7 (S281) ◽  
pp. 240-243
Author(s):  
Maxwell Moe ◽  
Rosanne Di Stefano
Keyword(s):  
Mass Transfer ◽  
First Principles ◽  
Type Ia Supernovae ◽  
Population Synthesis ◽  
Common Envelope ◽  
Tidal Interactions ◽  
Type Ia ◽  
Free Parameters ◽  
Binary Evolution ◽  
Ia Supernovae

AbstractComputing the rate of Type Ia supernovae (SNe Ia) from first principles is difficult because there are large uncertainties regarding several key binary processes such as common envelope evolution, tidal interactions, and the efficiency of mass transfer. Fortunately, a range of observational parameters of binaries in intermediate stages of evolution can help us model these processes in a way that is likely to mirror the true binary evolution. We discuss how this observationally-motivated approach may have the effect of increasing the predicted rate of single degenerate progenitors of SNe Ia, while simultaneously decreasing the number of double degenerate progenitors.

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