scholarly journals A circumbinary disc in the final stages of common envelope and the core-degenerate scenario for Type Ia supernovae

2011 ◽  
Vol 417 (2) ◽  
pp. 1466-1479 ◽  
Author(s):  
Amit Kashi ◽  
Noam Soker
2018 ◽  
Vol 14 (S343) ◽  
pp. 540-541
Author(s):  
Bo Wang

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.


2020 ◽  
Vol 497 (2) ◽  
pp. 1895-1903 ◽  
Author(s):  
E C Wilson ◽  
J Nordhaus

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.


2019 ◽  
Vol 490 (2) ◽  
pp. 2430-2435 ◽  
Author(s):  
Noam Soker

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.


2011 ◽  
Vol 7 (S281) ◽  
pp. 240-243
Author(s):  
Maxwell Moe ◽  
Rosanne Di Stefano

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.


2020 ◽  
Vol 633 ◽  
pp. A41
Author(s):  
Ren Song ◽  
Xiangcun Meng ◽  
Philipp Podsiadlowski ◽  
Yingzhen Cui

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.


2011 ◽  
Vol 7 (S281) ◽  
pp. 34-35
Author(s):  
Rosanne Di Stefano

AbstractEvery model for the progenitors of Type Ia supernovae (SNe Ia) requires that binaries pass through an epoch during which a white dwarf (WD) orbits a non-degenerate star. Depending on the mass of the WD, the radius of its companion, and the orbital separation, the WD may lens its companion. The lensing event would be an antitransit, an increase in light from the companion that can rise to the level of a percent or more, during an interval of hours. Antitransits are periodic. By studying them we can determine the properties of both the WD and its companion, as well as the characteristics of the orbit. Lensing events of this type are almost certain to be observed by the Kepler mission, while some can even be detected by ground-based surveys. Antitransits and transits will both provide valuable insight into the end states of common envelope evolution and of stable mass transfer, resolving issues that must be understood before we can fully unravel the progenitor puzzle.


2011 ◽  
Vol 7 (S281) ◽  
pp. 223-224
Author(s):  
Silvia Toonen ◽  
Gijs Nelemans ◽  
Simon Portegies Zwart

AbstractType Ia supernovae (SNe Ia) are very successfully used as standard candles on cosmological distance scales, but so far the nature of the progenitor(s) is unclear. A possible scenario for SNe Ia are merging carbon/oxygen white dwarfs with a combined mass exceeding the Chandrasekhar mass. We determine the theoretical rates and delay time distribution of these mergers for two different common envelope prescriptions and metallicities. The shape of the delay time distributions is rather insensitive to the assumptions. The normalization is a factor ~3–13 too low compared to observations.


Sign in / Sign up

Export Citation Format

Share Document