Partly burnt runaway stellar remnants from peculiar thermonuclear supernovae

Raddi, R.; Hollands, Mark; Koester, D.; Hermes, J. J.; Gänsicke, B. T.; Heber, U.; Shen, Ken J.; Townsley, Dean M.; Pala, A. F.; Reding, Joshua S.; Toloza, Odette; Pelisoli, Ingrid; Geier, S.; Fusillo, N. P. Gentile; Munari, U.; Strader, Jay

doi:10.1093/mnras/stz1618

Cited by 55 publications

(57 citation statements)

References 120 publications

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“…We conclude that this star merged out of the evolution of two CO WDs resulting in a total age >10 Gyr. Our results exclude earlier suggestions (Ruffini & Casey 2019) that LP 93-21 belongs to a class of surviving remnants of subluminous Type Iax supernova events (Vennes et al 2017;Raddi et al 2019).…”

Section: Discussionsupporting

confidence: 79%

An ancient double degenerate merger in the Milky Way halo

Kawka

Vennes

Ferrario

2019

Monthly Notices of the Royal Astronomical Society: Letters

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We present an analysis and re-appraisal of the massive, carbon-enriched (DQ) white dwarf (WD) LP 93-21. Its high mass (≈ 1 M ) and membership to the class of warm DQ WDs, combined with its peculiar halo kinematics suggest that this object is the product of an ancient stellar merger event, most likely that of two WDs. Furthermore, the kinematics places this object on a highly retrograde orbit driven by the accretion of a dwarf galaxy onto the Milky Way that occurred at a red shift greater than 1.5. As the product of a stellar merger LP 93-21 is probably representative of the whole class of warm/hot DQ WDs.

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Section: Discussionsupporting

confidence: 79%

An ancient double degenerate merger in the Milky Way halo

Kawka

Vennes

Ferrario

2019

Monthly Notices of the Royal Astronomical Society: Letters

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“…It is possible this explosion does not completely disrupt the white dwarf, leaving a bound remnant 149 . Surviving examples of such incomplete explosions may have been discovered in our Galaxy as fast-moving white dwarfs with unusual abundances 150,151 .…”

Section: The Thermonuclear Supernova Zoomentioning

confidence: 99%

Observational properties of thermonuclear supernovae

2019

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The explosive death of a star as a supernova is one of the most dramatic events in the Universe. Supernovae have an outsized impact on many areas of astrophysics: they are major contributors to the chemical enrichment of the cosmos and significantly influence the formation of subsequent generations of stars and the evolution of galaxies. Here we review the observational properties of thermonuclear supernovae, exploding white dwarf stars resulting from the stellar evolution of low-mass stars in close binary systems. The best known objects in this class are type Ia supernovae (SN Ia), astrophysically important in their application as standardisable candles to measure cosmological distances and the primary source of iron group elements in the Universe. Surprisingly, given their prominent role, SN Ia progenitor systems and explosion mechanisms are not fully understood; the observations we describe here provide constraints on models, not always in consistent ways. Recent advances in supernova discovery and follow-up have shown that the class of thermonuclear supernovae includes more than just SN Ia, and we characterise that diversity in this review.The modern classification scheme for supernovae traces back to Minkowski 1 who in 1941 split "Type I" from "Type II" supernovae based on optical spectra. Further subdivision of these basic classes has continued on an empirical basis 2, 3 , and in our review we describe the observational properties of what are now called SN Ia, along with other similar objects. The observational classification effort arises from a desire for physical understanding of these objects, explaining our use of the term thermonuclear supernovae in the title. That categorisation is based on the explosion mechanism: objects where the energy released in the explosion is primarily the result of thermonuclear fusion. Given our current state of knowledge, we could equally well call this a review of the observational properties of white dwarf supernovae, a categorisation based on the kind of object that explodes. This is contrasted with core-collapse or massive star supernovae, respectively, in the explosion mechanism or exploding object categorisations. Unlike those objects, where clear observational evidence exists for massive star progenitors and corecollapse (from both neutrino emission and remnant pulsars), the direct evidence for thermonuclear supernova explosions of white dwarfs is limited 4, 5 and not necessarily simply interpretable 6, 7 . Nevertheless, the indirect evidence is strong, though many open questions about the progenitor systems and explosion mechanisms remain.SN Ia are important both to the evolution of the Universe and to our understanding of it. As standardisable candles whose distance can be observationally inferred 8 , SN Ia have a starring role in the discovery of the accelerating expansion of the Universe 9, 10 and in measurement of its current expansion rate 11 . SN Ia are also major contributors to the chemical enrichment of the Universe, producing most of its iron 12 and elem...

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“…In Raddi et al (2018Raddi et al ( , 2019, the abundance patterns are extracted from the spectra of some low-mass WDs with unusually high metal fractions. They are also traveling with a high velocity.…”

Section: Application To Observed Low-mass Wdsmentioning

confidence: 99%

Explosive Nucleosynthesis in Near-Chandrasekhar Mass White Dwarf Models for Type Iax Supernovae: Dependence on Model Parameters

Leung

Nomoto

2020

ApJ

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The recently observed diversity of Type Ia supernovae (SNe Ia) has motivated us to conduct the theoretical modeling of SNe Ia for a wide parameter range. In particular, the origin of Type Iax supernovae (SNe Iax) has been obscure. Following our earlier work on the parameter dependence of SN Ia models, we focus on SNe Iax in the present study. For a model of SNe Iax, we adopt the currently leading model of pure turbulent deflagration of near-Chandrasekhar mass C+O white dwarfs (WDs). We carry out two-dimensional hydrodynamical simulations of the propagation of the deflagration wave, which leaves a small WD remnant behind and ejects nucleosynthesis materials. We show how the explosion properties, such as nucleosynthesis and explosion energy, depend on the model parameters, such as central densities and compositions of the WDs (including the hybrid WDs), turbulent flame prescription, and initial flame geometry. We extract the associated observables in our models and compare with the recently discovered low-mass WDs with unusual surface abundance patterns and the abundance patterns of some SN remnants. We provide the nucleosynthesis yield tables for applications to stellar archeology and galactic chemical evolution. Our results are compared with the representative models in the literature.

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Partly burnt runaway stellar remnants from peculiar thermonuclear supernovae

Cited by 55 publications

References 120 publications

An ancient double degenerate merger in the Milky Way halo

An ancient double degenerate merger in the Milky Way halo

Observational properties of thermonuclear supernovae

Explosive Nucleosynthesis in Near-Chandrasekhar Mass White Dwarf Models for Type Iax Supernovae: Dependence on Model Parameters

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