The demographics of neutron star – white dwarf mergers

Context. The mergers of neutron stars (NSs) and white dwarfs (WDs) could give rise to explosive transients, potentially observable with current and future transient surveys. However, the expected properties and distribution of such events is not well understood. Aims. Here we characterise the rates of such events, their delay-time distributions, their progenitors, and the distribution of their properties. Methods. We use binary population synthesis models and consider a wide range of initial conditions and physical processes. In particular we consider different common-envelope evolution models and different NS natal kick distributions. We provide detailed predictions arising from each of the models considered. Results. We find that the majority of NS–WD mergers are born in systems in which mass-transfer played an important role, and the WD formed before the NS. For the majority of the mergers the WDs have a carbon-oxygen composition (60−80%) and most of the rest are with oxygen-neon WDs. The time-integrated rates of NS–WD mergers are in the range of 3−15% of the type Ia supernovae (SNe) rate. Their delay-time distribution is very similar to that of type Ia SNe, but is slightly biased towards earlier times. They typically explode in young 100 Myr < τ < 1 Gyr environments, but have a tail distribution extending to long, gigayear-timescales. Models including significant kicks give rise to relatively wide offset distribution extending to hundreds of kiloparsecs. Conclusions. The demographic and physical properties of NS–WD mergers suggest they are likely to be peculiar type Ic-like SNe, mostly exploding in late-type galaxies. Their overall properties could be related to a class of recently observed rapidly evolving SNe, while they are less likely to be related to the class of Ca-rich SNe.

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Common envelope to explosion delay time of Type Ia supernovae

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2817 ◽

2019 ◽

Vol 490 (2) ◽

pp. 2430-2435 ◽

Cited By ~ 4

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.

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Double White Dwarf Merger Rates

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312015086 ◽

2011 ◽

Vol 7 (S281) ◽

pp. 223-224

Author(s):

Silvia Toonen ◽

Gijs Nelemans ◽

Simon Portegies Zwart

Keyword(s):

White Dwarf ◽

Delay Time ◽

Time Distribution ◽

White Dwarfs ◽

Type Ia Supernovae ◽

Common Envelope ◽

Cosmological Distance ◽

Type Ia ◽

Ia Supernovae

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.

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The delay time distribution of type Ia supernovae: theory and observation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310002486 ◽

2009 ◽

Vol 5 (S262) ◽

pp. 31-35

Author(s):

Dany Vanbeveren ◽

Nicki Mennekens ◽

Jean-Pierre De Greve ◽

Erwin De Donder

Keyword(s):

Delay Time ◽

Time Distribution ◽

Theoretical Models ◽

Roche Lobe ◽

Type Ia Supernovae ◽

Population Number ◽

Common Envelope ◽

Type Ia ◽

Red Giant ◽

Ia Supernovae

AbstractUsing a population number synthesis code, the theoretical time distributions of type Ia supernovae in starburst galaxies are calculated, using competing models for the formation of such events: the single degenerate (a white dwarf accreting matter from a late main sequence or red giant companion) and double degenerate (the merger of two white dwarfs) scenario. The code includes the latest results in determining the progenitors for both models. Examples are the mass stripping effect in the case of the single degenerate scenario and the differentiation between the α- (based on the balance of energy) and γ- (based on the balance of angular momentum) description of energy conversion during common envelope evolution of binaries. The shape and extent of the obtained delay time distributions critically depends on which formation scenario is used. Comparing these results to the latest observed distributions allows to draw conclusions about the constraints put on the theoretical models by these observations. We also specifically investigate the influence of the degree of conservatism during Roche lobe overflow on the delay time distribution. We conclude that the single degenerate scenario alone cannot reproduce the observed delay time distributions, and that most double degenerate type Ia supernovae are formed through a quasi-conservative Roche lobe overflow phase followed by spiral-in, as opposed to a double common envelope evolution.

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

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318005689 ◽

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.

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

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312015128 ◽

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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Delay Time Distribution Measurement of Type Ia Supernovae by the Subaru/XMM-Newton Deep Survey and Implications for the Progenitor

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/60.6.1327 ◽

2008 ◽

Vol 60 (6) ◽

pp. 1327-1346 ◽

Cited By ~ 164

Author(s):

Tomonori Totani ◽

Tomoki Morokuma ◽

Takeshi Oda ◽

Mamoru Doi ◽

Naoki Yasuda

Keyword(s):

Delay Time ◽

Time Distribution ◽

Type Ia Supernovae ◽

Distribution Measurement ◽

Type Ia ◽

Deep Survey ◽

Ia Supernovae

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Constraining the Properties of SNe Ia Progenitors from Light Curves

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312015256 ◽

2011 ◽

Vol 7 (S281) ◽

pp. 309-313 ◽

Cited By ~ 1

Author(s):

B. Sadler ◽

Peter Hoeflich ◽

E. Baron ◽

K. Krisciunas ◽

G. Folatelli ◽

...

Keyword(s):

Main Sequence ◽

Light Curves ◽

Overdetermined System ◽

Model Calculations ◽

Common Envelope ◽

Wide Range ◽

Accretion Rates ◽

Type Ia ◽

Closing The Gap ◽

Ia Supernovae

AbstractWe present an analysis of high precision V light curves (LC) for 18 local Type Ia supernovae (SNe Ia) as obtained with the same telescope and setup at the Las Campanas Observatory (LCO). This homogeneity provides an intrinsic accuracy of a few hundredths of a magnitude with respect to individual LCs and between different objects. Based on the single degenerate (SD) scenario, we identify patterns which have been predicted by model calculations as signatures of the progenitor and accretion rate which change the explosion energy and the amount of electron capture, respectively. Using these templates as principle components and the overdetermined system of SNe pairs, we reconstruct the properties of progenitors and progenitor systems. All LCO SNe Ia follow the brightness decline relation except 2001ay. After subtraction of the two components, the remaining scatter is reduced to ≈0.01m−0.03m. SNe Ia seem to originate from progenitors with main-sequence masses MMS > 3 M⊙ with the exception of two subluminous SNe Ia with MMS < 2 M⊙. The component analysis indicates a wide range of accretion rates in the progenitor systems closing the gap to accretion induced collapses (AIC). SN1991t-like objects show differences in decline rate (dm15) but no tracers of our secondary parameters. This may point to a different origin such as the double degenerate or pulsating delayed detonation scenarios. SN2001ay does not follow the decline relation. It can be understood in the framework of C-rich white dwarfs (WDs), and this group may produce an anti-Phillips relation. We suggest that this may be a result of a common envelope phase and mixing during central He burning as in SN1987A.

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Delay-Time Distribution of Type-Ia Supernovae: Theory versus Observation

10.1063/1.3536376 ◽

2010 ◽

Author(s):

Nicki Mennekens ◽

Dany Vanbeveren ◽

Jean-Pierre De Greve ◽

Erwin De Donder ◽

Vicky Kologera ◽

...

Keyword(s):

Delay Time ◽

Time Distribution ◽

Type Ia Supernovae ◽

Type Ia ◽

Theory Versus ◽

Ia Supernovae

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Galactic Chemical Evolution in the Context of the Recently Revealed SNe Ia Delay Time Distribution

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312015153 ◽

2011 ◽

Vol 7 (S281) ◽

pp. 251-252

Author(s):

Takuji Tsujimoto

Keyword(s):

Chemical Evolution ◽

Delay Time ◽

Time Distribution ◽

Chemical Properties ◽

Thin Disk ◽

Chemical Enrichment ◽

Precise Knowledge ◽

The Galaxy ◽

Type Ia ◽

Ia Supernovae

AbstractThe Galaxy is composed of four distinct structures, i.e., halo, bulge, and thick and thin disks, that are formed and evolved on different timescales; thus accordingly the speeds of chemical enrichment are different from one another, which is imprinted in individual stellar abundances. To decipher them, precise knowledge of the timing of the release of nucleosynthesis materials from various production sites is critical. The delay time distribution (DTD) of Type Ia supernovae (SNe Ia), recently revealed by the SNe Ia surveys of external galaxies, is incorporated into the models of chemical evolution for each structure. Here we report that the observed chemical properties for the thin and thick disks are compatible with a new SNe Ia DTD, and suggests a close chemical connection between the two in the way that the thin disk is formed from gas left after thick disk formation. This nicely explains the lack of thin disk stars with [Fe/H] ≲ −0.8. In this new context, a top-heavy IMF for the bulge is firmly confirmed. Finally we discuss the possibility of some modification of the DTD that might be considered for the halo case.

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