scholarly journals Spectral signatures of H-rich material stripped from a non-degenerate companion by a Type Ia supernova

2020 ◽  
Vol 638 ◽  
pp. A80 ◽  
Author(s):  
Luc Dessart ◽  
Douglas C. Leonard ◽  
Jose L. Prieto
Keyword(s):  
Equivalent Width ◽  
Giant Planet ◽  
Type Ia Supernovae ◽  
Circumstellar Material ◽  
Type Ia ◽  
Balmer Lines ◽  
Non Local ◽  
Hydrodynamical Simulations ◽  
Rich Material ◽  
Ia Supernovae

The single-degenerate scenario for Type Ia supernovae should yield metal-rich ejecta that enclose some stripped material from the non-degenerate H-rich companion star. We present a large grid of non-local thermodynamic equilibrium steady-state radiative transfer calculations for such hybrid ejecta and provide analytical fits for the Hα luminosity and equivalent width. Our set of models covers a range of masses for 56Ni and the ejecta, for the stripped material (Mst), and post-explosion epochs from 100 to 300 d. The brightness contrast between stripped material and metal-rich ejecta challenges the detection of H I and He I lines prior to ~100 d. Intrinsic and extrinsic optical depth effects also influence the radiation emanating from the stripped material. This inner denser region is marginally thick in the continuum and optically thick in all Balmer lines. The overlying metal-rich ejecta blanket the inner regions, completely below about 5000 Å, and more sparsely at longer wavelengths. As a consequence, Hβ should not be observed for all values of Mst up to at least 300 days, while Hα should be observed after ~100 d for all Mst ≥ 0.01 M⊙. Observational non-detections capable of limiting the Hα equivalent width to <1 Å set a formal upper limit of Mst < 0.001M⊙. This contrasts with the case of circumstellar-material (CSM) interaction, not subject to external blanketing, which should produce Hα and Hβ lines with a strength dependent primarily on CSM density. We confirm previous analyses that suggest low values of order 0.001 M⊙ for Mst to explain the observations of the two Type Ia supernovae with nebular-phase Hα detection, in conflict with the much greater stripped mass predicted by hydrodynamical simulations for the single-degenerate scenario. A more likely solution is the double-degenerate scenario, together with CSM interaction, or enclosed material from a tertiary star in a triple system or from a giant planet.

scholarly journals Monte Carlo radiative transfer for the nebular phase of Type Ia supernovae

2019 ◽  
Vol 492 (2) ◽  
pp. 2029-2043 ◽  
Author(s):  
L J Shingles ◽  
S A Sim ◽  
M Kromer ◽  
K Maguire ◽  
M Bulla ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Atomic Data ◽  
Type Ia Supernovae ◽  
Data Set ◽  
High Ionization ◽  
Type Ia ◽  
Non Local ◽  
Ionization Balance ◽  
Ia Supernovae ◽  
Modest Effect

ABSTRACT We extend the range of validity of the artis 3D radiative transfer code up to hundreds of days after explosion, when Type Ia supernovae (SNe Ia) are in their nebular phase. To achieve this, we add a non-local thermodynamic equilibrium population and ionization solver, a new multifrequency radiation field model, and a new atomic data set with forbidden transitions. We treat collisions with non-thermal leptons resulting from nuclear decays to account for their contribution to excitation, ionization, and heating. We validate our method with a variety of tests including comparing our synthetic nebular spectra for the well-known one-dimensional W7 model with the results of other studies. As an illustrative application of the code, we present synthetic nebular spectra for the detonation of a sub-Chandrasekhar white dwarf (WD) in which the possible effects of gravitational settling of 22Ne prior to explosion have been explored. Specifically, we compare synthetic nebular spectra for a 1.06 M⊙ WD model obtained when 5.5 Gyr of very efficient settling is assumed to a similar model without settling. We find that this degree of 22Ne settling has only a modest effect on the resulting nebular spectra due to increased 58Ni abundance. Due to the high ionization in sub-Chandrasekhar models, the nebular [Ni ii] emission remains negligible, while the [Ni iii] line strengths are increased and the overall ionization balance is slightly lowered in the model with 22Ne settling. In common with previous studies of sub-Chandrasekhar models at nebular epochs, these models overproduce [Fe iii] emission relative to [Fe ii] in comparison to observations of normal SNe Ia.

scholarly journals Star formation in early-type galaxies: the role of stellar winds and kinematics

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Silvia Pellegrini ◽  
Andrea Negri ◽  
Luca Ciotti
Keyword(s):  
Star Formation ◽  
High Resolution ◽  
Type Ia Supernovae ◽  
Stellar Winds ◽  
Early Type ◽  
Stellar Component ◽  
Type Ia ◽  
Hydrodynamical Simulations ◽  
Ia Supernovae

AbstractEarly-type galaxies (ETGs) host a hot ISM produced mainly by stellar winds, and heated by Type Ia supernovae and the thermalization of stellar motions. High resolution 2D hydrodynamical simulations showed that ordered rotation in the stellar component results in the formation of a centrifugally supported cold equatorial disc. In a recent numerical investigation we found that subsequent generations of stars are formed in this cold disc; this process consumes most of the cold gas, leaving at the present epoch cold masses comparable to those observed. Most of the new stellar mass formed a few Gyrs ago, and resides in a disc.

scholarly journals Understanding nebular spectra of Type Ia supernovae

2020 ◽  
Vol 494 (2) ◽  
pp. 2221-2235 ◽  
Author(s):  
Kevin D Wilk ◽  
D John Hillier ◽  
Luc Dessart
Keyword(s):  
Radiative Transfer ◽  
Local Thermodynamic Equilibrium ◽  
Diagnostic Feature ◽  
Type Ia Supernovae ◽  
Thermal Heating ◽  
One Dimensional ◽  
Type Ia ◽  
Natural Mechanism ◽  
Non Local ◽  
Ia Supernovae

ABSTRACT In this study, we present one-dimensional, non-local-thermodynamic-equilibrium, radiative transfer simulations (using cmfgen) in which we introduce micro-clumping at nebular times into two Type Ia supernova ejecta models. We use one sub-Chandrasekhar (sub-MCh) ejecta model with 1.04 M⊙ and one Chandrasekhar (MCh) ejecta model with 1.40 M⊙. We introduce clumping factors f = 0.33, 0.25, and 0.10, which are constant throughout the ejecta, and compare results to the unclumped f = 1.0 case. We find that clumping is a natural mechanism to reduce the ionization of the ejecta, reducing emission from [Fe iii], [Ar iii], and [S iii] by a factor of a few. For decreasing values of the clumping factor f, the [Ca ii] λλ7291,7324 doublet became a dominant cooling line for our MCh model but remained weak in our sub-MCh model. Strong [Ca ii] λλ7291,7324 indicates non-thermal heating in that region and may constrain explosion modelling. Due to the low abundance of stable nickel, our sub-MCh model never showed the [Ni ii] 1.939-μm diagnostic feature for all clumping values.

scholarly journals A statistical analysis of circumstellar material in Type Ia supernovae

2013 ◽  
Vol 436 (1) ◽  
pp. 222-240 ◽  
Author(s):  
K. Maguire ◽  
M. Sullivan ◽  
F. Patat ◽  
A. Gal-Yam ◽  
I. M. Hook ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Type Ia Supernovae ◽  
Circumstellar Material ◽  
Type Ia ◽  
Ia Supernovae

scholarly journals Circumstellar Material in Type Ia Supernovae via Sodium Absorption Features

Science ◽  
2011 ◽  
Vol 333 (6044) ◽  
pp. 856-859 ◽  
Author(s):  
A. Sternberg ◽  
A. Gal-Yam ◽  
J. D. Simon ◽  
D. C. Leonard ◽  
R. M. Quimby ◽  
...  
Keyword(s):  
Sodium Absorption ◽  
Type Ia Supernovae ◽  
Circumstellar Material ◽  
Type Ia ◽  
Ia Supernovae ◽  
Absorption Features

scholarly journals Evidence for Circumstellar Material in Type Ia Supernovae via Sodium Absorption Features

2011 ◽  
Vol 7 (S281) ◽  
pp. 299-302
Author(s):  
Assaf Sternberg
Keyword(s):  
White Dwarf ◽  
Velocity Structure ◽  
Close Binary System ◽  
Close Binary ◽  
Sodium Absorption ◽  
Type Ia Supernovae ◽  
Circumstellar Material ◽  
Type Ia ◽  
Ia Supernovae ◽  
Degenerate Model

AbstractType Ia supernovae are very good tools for measuring distances on a cosmic scale. The consensus view is that mass transfer onto a white dwarf in a close binary system leads to a thermonuclear explosion, though the nature of the mass donor is still uncertain. In the single-degenerate model it is a main-sequence star or an evolved star. In the double-degenerate model it is another white dwarf. We study the velocity structure of absorbing material along the line of sight to 35 Type Ia supernovae and find a statistical preference for blueshifted structures, likely arising in gas outflows from the supernova progenitor systems, consistent with a single-degenerate progenitor for a substantial fraction of Type Ia supernovae in nearby spiral galaxies.

scholarly journals EVIDENCE FOR ASYMMETRIC DISTRIBUTION OF CIRCUMSTELLAR MATERIAL AROUND TYPE Ia SUPERNOVAE

2012 ◽  
Vol 754 (2) ◽  
pp. L21 ◽  
Author(s):  
Francisco Förster ◽  
Santiago González-Gaitán ◽  
Joseph Anderson ◽  
Sebastián Marchi ◽  
Claudia Gutiérrez ◽  
...  
Keyword(s):  
Type Ia Supernovae ◽  
Asymmetric Distribution ◽  
Circumstellar Material ◽  
Type Ia ◽  
Ia Supernovae

scholarly journals The single degenerate channel for the progenitors of Type Ia supernovae

2008 ◽  
Vol 4 (S252) ◽  
pp. 379-382
Author(s):  
Xiangcun Meng ◽  
Xuefei Chen ◽  
Zhanwen Han
Keyword(s):  
Stellar Evolution ◽  
Supernova Remnants ◽  
Birth Rate ◽  
Binary Systems ◽  
Supernova Explosion ◽  
Type Ia Supernovae ◽  
Type Ia ◽  
Rich Material ◽  
The Moment ◽  
Ia Supernovae

AbstractWe have carried out a detailed study of the single-degenerate channel for the progenitors of type Ia supernovae (SNe Ia). In the model, a carbon-oxygen white dwarf (CO WD) accretes hydrogen-rich material from an unevolved or a slightly evolved non-degenerate companion to increase its mass to Chandrasekhar mass limit. Incorporating the prescription of Hachisuet al. (1999a) for the accretion efficiency into Eggleton's stellar evolution code and assuming that the prescription is valid for all metallicities, we performed binary stellar evolution calculations for more than 25,000 close WD binary systems with various metallicities. The initial parameter spaces for SNe Ia are presented in an orbital period-secondary mass (logPi,M2i) plane for eachZ.Adopting the results above, we studied the birth rate of SNe Ia for variousZvia binary population synthesis. From the study, we see that for a highZ, SNe Ia occur systemically earlier and the peak value of the birth rate is larger if a single starburst is assumed. The Galactic birth rate from the channel is lower than (but comparable to) that inferred from observations.We also showed the distributions of the parameters of the binary systems at the moment of supernova explosion and the distributions of the properties of companions after supernova explosion. The former provides physics input to simulate the interaction between supernova ejecta and its companion, and the latter is helpful for searching the companions in supernova remnants.

scholarly journals Connecting Recurrent Novae to [Some] Type Ia Supernovae

2011 ◽  
Vol 7 (S281) ◽  
pp. 291-298
Author(s):  
Ferdinando Patat
Keyword(s):  
Type Ia Supernovae ◽  
Circumstellar Material ◽  
Type Ia ◽  
Recent Developments ◽  
Ia Supernovae ◽  
Circumstellar Environment

AbstractIn this review, I summarize the observational attempts made so far to unveil the nature of the progenitor system(s) of Type Ia supernovae. In particular, I focus on the most recent developments that followed the claimed detection of circumstellar material around a few events, and on the link this possibly establishes with recurrent novae. In this framework, I then discuss the case of RS Oph, what we know of its circumstellar environment, and what this is telling us about its supposed connection to Type Ia supernovae explosions.

scholarly journals Limits on stable iron in Type Ia supernovae from near-infrared spectroscopy

2018 ◽  
Vol 620 ◽  
pp. A200 ◽  
Author(s):  
A. Flörs ◽  
J. Spyromilio ◽  
K. Maguire ◽  
S. Taubenberger ◽  
W. E. Kerzendorf ◽  
...  
Keyword(s):  
Near Infrared ◽  
Type Ia Supernovae ◽  
Near Infrared Spectra ◽  
Theoretical Predictions ◽  
Type Ia ◽  
Iron Nickel ◽  
Non Local ◽  
Line Widths ◽  
Measured Line ◽  
Ia Supernovae

We obtained optical and near infrared spectra of Type Ia supernovae (SNe Ia) at epochs ranging from 224 to 496 days after the explosion. The spectra show emission lines from forbidden transitions of singly ionised iron and cobalt atoms. We used non-local thermodynamic equilibrium (NLTE) modelling of the first and second ionisation stages of iron, nickel, and cobalt to fit the spectra using a sampling algorithm allowing us to probe a broad parameter space. We derive velocity shifts, line widths, and abundance ratios for iron and cobalt. The measured line widths and velocity shifts of the singly ionised ions suggest a shared emitting region. Our data are fully compatible with radioactive 56Ni decay as the origin for cobalt and iron. We compare the measured abundance ratios of iron and cobalt to theoretical predictions of various SN Ia explosion models. These models include, in addition to 56Ni, different amounts of 57Ni and stable 54,56Fe. We can exclude models that produced only 54,56Fe or only 57Ni in addition to 56Ni. If we consider a model that has 56Ni, 57Ni, and 54,56Fe then our data imply that these ratios are 54,56Fe / 56Ni = 0.272 ± 0.086 and 57Ni / 56Ni = 0.032 ± 0.011.

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