Modeling Type Ia supernova explosions

Röpke, F. K.; Seitenzahl, Ivo R.; Benitez, S.; Fink, Michael; Pakmor, Rüediger; Kromer, M.; Sim, Stuart; Ciaraldi-Schoolmann, Franco; Hillebrandt, W.

doi:10.1016/j.ppnp.2011.01.026

Cited by 26 publications

(24 citation statements)

References 69 publications

(85 reference statements)

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“…It is still under debate whether core-normal and subluminous Type Ia are a single class (Höflich et al 2002), or form separate groups Sim et al 2010;Röpke et al 2011). Both sub-Chandrasekhar mass WDs and WD mergers have been suggested as possible mechanisms.…”

Section: Sub-chandrasekhar Mass Explosions and Mergersmentioning

confidence: 99%

VLT Spectropolarimetry of the Type Ia SN 2005ke

Patat¹,

Hoêflich²,

Baade³

et al. 2012

A&A

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Aims. In this study we try to answer the question whether or not subluminous Type Ia supernovae have additional distinctive properties when examined from the point of view of the explosion geometry. Methods. We have performed optical spectropolarimetric observations of the Type Ia SN 2005ke at 3 epochs (days −8, −7, and +76). The explosion properties are derived by comparing the data to explosion and radiation transfer models. Results. The supernova shows polarimetric properties that are very similar to the only other subluminous event for which spectropolarimetry is available, i.e. SN 1999by. The data present a very marked dominant axis, which is shared by both the continuum and lines such as Si ii λ6355, suggesting that the relatively large, global asymmetry is common to the photosphere and the line-forming region. The maximum polarization degree observed in the Si ii λ6355 absorption reaches 0.39 ± 0.08%. At variance with what is seen in core-normal Type Ia, SN 2005ke displays significant continuum polarization, which grows from the blue to the red and peaks at about 7000 Å, reaching ∼0.7%. The properties of the polarization and flux spectra can be understood within the framework of a subluminous delayed-detonation (DD), or pulsating DD scenario, or white dwarf (WD) mergers. The difference in appearance with respect to core-normal SNe Ia is caused by low photospheric temperatures in combination with layers of unburned C, and more massive layers of the products of explosive C and O burning. The comparatively high level of continuum polarization is explained in terms of a significant global asymmetry (∼15%), which is well reproduced by an oblate ellipsoidal geometry within the general context of a DD explosion. Conclusions. Our results suggest that SN 2005ke arose either from a single-degenerate system in which the WD is especially rapidly rotating, close to the break-up velocity, or from a double-degenerate merger. Based on the current polarization data, we cannot distinguish between these two possibilities. Possible tests are discussed.

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Section: Sub-chandrasekhar Mass Explosions and Mergersmentioning

confidence: 99%

VLT Spectropolarimetry of the Type Ia SN 2005ke

Patat¹,

Hoêflich²,

Baade³

et al. 2012

A&A

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“…Nowadays, sofisticated threedimensional simulations of SNIa based on different flavours of the delayed-detonation model (e.g. Gamezo et al 2003;Meakin et al 2009;Bravo et al 2009;Röpke et al 2011) are confronted with data in order to explain increasingly subtle observational details (Mazzali et al 2007;Kasen et al 2009;Maeda et al 2010). These numerical simulations have taught us that the outcome of the explosion is very sensitive to the runaway conditions (e.g.…”

Section: Introductionmentioning

confidence: 99%

Type Ia supernovae and the¹²C+¹²C reaction rate

Bravo

Piersanti

Domínguez

et al. 2011

A&A

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Context. Even if the 12 C+ 12 C reaction plays a central role in the ignition of type Ia supernovae (SNIa), the experimental determination of its cross-section at astrophysically relevant energies (E 2 MeV) has never been made. The profusion of resonances throughout the measured energy range has led to speculation that there is an unknown resonance at E 0 ∼ 1.5 MeV possibly as strong as the one measured for the resonance at 2.14 MeV, i.e. (ωγ) R = 0.13 meV. Aims. We study the implications that such a resonance would have for our knowledge of the physics of SNIa, paying special attention to the phases that go from the crossing of the ignition curve to the dynamical event.Methods. We use one-dimensional hydrostatic and hydrodynamic codes to follow the evolution of accreting white dwarfs until they grow close to the Chandrasekhar mass and explode as SNIa. In our simulations, we account for a low-energy resonance by exploring the parameter space allowed by experimental data. Results. A change in the 12 C+ 12 C rate similar to the one explored here would have profound consequences for the physical conditions in the SNIa explosion, namely the central density, neutronization, thermal profile, mass of the convective core, location of the runaway hot spot, or time elapsed since crossing the ignition curve. For instance, with the largest resonance strength we use, the time elapsed since crossing the ignition curve to the supernova event is shorter by a factor ten than for models using the standard rate of 12 C+ 12 C, and the runaway temperature is reduced from ∼8.14 × 10 8 K to ∼4.26 × 10 8 K. On the other hand, a resonance at 1.5 MeV, with a strength ten thousand times smaller than the one measured at 2.14 MeV, but with an α/p yield ratio substantially different from 1 would have a sizeable impact on the degree of neutronization of matter during carbon simmering. Conclusions. A robust understanding of the links between SNIa properties and their progenitors will not be attained until the 12 C+ 12 C reaction rate is measured at energies ∼1.5 MeV.

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“…These could be supernovae, such as from core-collapse of a massive star at its terminal phase of stellar evolution (supernova types II and Ib,Ic), thermonuclear supernovae related to disruptions of a white dwarf star (supernovae type Ia), or novae, which are thermonuclear events on the surface of a white dwarf star, which are not disruptive to the host star itself (reviews and more detail on supernova variants can be found in [147] and [109]). Thermonuclear events on more-compact objects such as neutron stars and black holes will be less likely to lead to significant expansion of the nuclear-burning site, and thus remain non-transparent to gamma-rays produced herein; on neutron star 16 O cosmic ray / ISM interactions surfaces, such events are termed type-I X-ray bursts [121].…”

Section: Cosmic Gamma-rays and Their Spectramentioning

confidence: 99%

“…Currently-discussed models 13 are (i) explosions triggered in white dwarf central regions as the Chandrasekhar mass limit is reached, (ii) explosions triggered by an off-center event such as a He-shell flash on white dwarfs of a broader mass range, and (iii) explosions resulting from merging of two white dwarfs as it may terminate the evolution of a binary system. More complex scenarios of binary evolution with recurrent pulsations culminating in a supernova are also discussed [110]. In all cases, the runaway nuclear carbon burning will provide the energy which disrupts the white dwarf; this is the commonly agreed part of SNIa models (see [48,110] for recent reviews).…”

Section: Supernovae Of Type Iamentioning

confidence: 99%

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Cosmic Gamma-Ray Spectroscopy

Diehl

2013

Astronomical Review

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Penetrating gamma-rays require complex instrumentation for astronomical spectroscopy measurements of gamma-rays from cosmic sources. Multiple-interaction detectors in space combined with sophisticated postprocessing of detector events on ground have lead to a spectroscopy performance which is now capable to provide new astrophysical insights. Spectral signatures in the MeV regime originate from transitions in the nuclei of atoms (rather than in their electron shell). Nuclear transitions are stimulated by either radioactive decays or high-energy nuclear collisions such as with cosmic rays. Gamma-ray lines have been detected from radioactive isotopes produced in nuclear burning inside stars and supernovae, and from energetic-particle interactions in solar flares. Radioactive-decay gamma-rays from 56 Ni directly reflect the source of supernova light. 44 Ti is produced in core-collapse supernova interiors, and the paucity of corresponding 44 Ti gamma-ray line sources reflects the variety of dynamical conditions herein. 26 Al and 60 Fe are dispersed in interstellar space from massive-star nucleosynthesis over millions of years. Gamma-rays from their decay are measured in detail by gamma-ray telescopes, astrophysical interpretations reach from massive-star interiors to dynamical processes in the interstellar medium. Nuclear de-excitation gamma-ray lines have been found in solar-flare events, and convey information about energetic-particle production in these events, and their interaction in the solar atmosphere. The annihilation of positrons leads to another type of cosmic gamma-ray source. The characteristic annihilation gamma-rays at 511 keV have been measured long ago in solar flares, and now throughout the interstellar medium of our Milky Way galaxy. But now a puzzle has appeared, as a surprising predominance of the central bulge region was determined. This requires either new positron sources or transport processes not yet known to us. In this paper we discuss instrumentation and data processing for cosmic gamma-ray spectroscopy, and the astrophysical issues and insights from these measurements.

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Modeling Type Ia supernova explosions

Cited by 26 publications

References 69 publications

VLT Spectropolarimetry of the Type Ia SN 2005ke

VLT Spectropolarimetry of the Type Ia SN 2005ke

Type Ia supernovae and the¹²C+¹²C reaction rate

Cosmic Gamma-Ray Spectroscopy

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Modeling Type Ia supernova explosions

Cited by 26 publications

References 69 publications

VLT Spectropolarimetry of the Type Ia SN 2005ke

VLT Spectropolarimetry of the Type Ia SN 2005ke

Type Ia supernovae and the12C+12C reaction rate

Cosmic Gamma-Ray Spectroscopy

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Type Ia supernovae and the¹²C+¹²C reaction rate