We revise the theoretical initial mass-final luminosity relation for progenitors of type IIP and IIL supernovae. The effects of the major uncertainties, as those due to the treatment of convection, semiconvection, rotation, mass loss, nuclear reaction rates and neutrinos production rates are discussed in some details. The effects of mass transfer between components of close-binary systems are also considered. By comparing the theoretical predictions to a sample of type II supernovae for which the initial mass of the progenitors and the pre-explosive luminosity are available, we conclude that stellar rotation may explain a few progenitors which appear brighter than expected in case of non-rotating models. In the most extreme case, SN2012ec, an initial rotational velocity up to 300 km s$^{-1}$ is required. Alternatively, these objects could be mass-loosing components of close binaries. However, most of the observed progenitors appear fainter than expected. This occurrence seems to indicate that the Compton and pair neutrino energy-loss rates, as predicted by the standard electro-weak theory, are not efficient enough and that an additional negative contribution to the stellar energy balance is required. We show that axions coupled with parameters accessible to currently planned experiments, such as IAXO and, possibly, Baby-IAXO and ALPS II, may account for the missing contribution to the stellar energy-loss.
We show the preliminary results of our search for the progenitor systems of type Ia supernovae (SNe Ia). We model binary populations our aim being to compare these models with the observations of detailed element abundances of the hot Intra-Cluster Medium.
The Mn to Cr mass ratio in supernova ejecta has recently been proposed as a tracer of Type Ia SN progenitor metallicity. We review the advantages and problems of this observable quantity, and discuss them in the framework of the Tycho Supernova Remnant. The fluxes of the Mn and Cr Kalpha lines in the X-ray spectra of Tycho observed by the Suzaku satellite suggests a progenitor of supersolar metallicity.
A precise knowledge of the masses of supernova progenitors is essential to answer various questions of modern astrophysics, such as those related to the dynamical and chemical evolution of Galaxies. In this paper we revise the upper bound for the mass of the progenitors of CO white dwarfs (\mup) and the lower bound for the mass of the progenitors of normal type II supernovae (\mups). In particular, we present new stellar models with mass between 7 and 10 \msun, discussing their final destiny and the impact of recent improvements in our understanding of the low energy rate of the \c12c12 reacti…
We use the results of a supernova light-curve population synthesis to predict the range of possible supernova light curves arising from a population of single-star progenitors that lead to type IIP supernovae. We calculate multiple models varying the initial mass, explosion energy, nickel mass and nickel mixing and then compare these to type IIP supernovae with detailed light curve data and pre-explosion imaging progenitor constraints. Where a good fit is obtained to observations, we are able to achieve initial progenitor and nickel mass estimates from the supernova lightcurve that are compara…
We present an analysis of Chandra observations of the position of ten nearby (< 25 Mpc) type Ia supernovae, taken before the explosions. No sources corresponding to progenitors were found in any of the observations. We calculated upper limits on the bolometric luminosities of the progenitors assuming black-body X-ray spectra with temperatures of 30-150 eV. This is inspired by the fact that luminous super-soft X-ray sources have been suggested as the direct progenitors of type Ia supernovae. The upper limits of two supernovae in our sample are comparable to the luminosities of the brightest obs…
SN 2007bi is an extremely luminous Type Ic supernova. This supernova is thought to be evolved from a very massive star, and two possibilities have been proposed for the explosion mechanism. One possibility is a pair-instability supernova with an M_{CO} ~ 100 M_sun CO core progenitor. Another possibility is a core-collapse supernova with M_{CO} ~ 40 M_sun. We investigate the evolution of very massive stars with main-sequence mass M_{MS} = 100 - 500 M_sun and Z_0 = 0.004, which is in the metallicity range of the host galaxy of SN 2007bi, to constrain the progenitor of SN 2007bi. The supernova ty…
In order to explore various aspects of stellar evolution, supernovae, gamma ray bursts and nucleosynthesis, we have developed a new efficient stellar evolution code. In this paper we describe this new code and compare the results with the ones calculated by the previous code. Specifically we focus on the progenitor evolution of lower end of the Fe-core collapse supernovae, and mass distribution of remnant neutron stars. We describe how different assumptions will lead different neutron star mass distribution. We also review recent works of our research group.
Aims. We present and analyse late-time observations of the type-Ib supernova with possible pre-supernova progenitor detection, iPTF13bvn, taken at $\sim$300 days after the explosion, and discuss these in the context of constraints on the supernova's progenitor. Previous studies have proposed two possible natures for the progenitor of the supernova, i.e. a massive Wolf-Rayet star or a lower-mass star in close binary system. Methods. Our observations show that the supernova has entered the nebular phase, with the spectrum dominated by Mg~I]$λλ$4571, [O~I]$λλ$6300, 6364, and [Ca~II]$λλ$7291, 7324…
We estimate the diffuse supernova neutrino background (DSNB) using the recent progenitor-dependent, long-term supernova simulations from the Basel group and including neutrino oscillations at several post-bounce times. Assuming multi-angle matter suppression of collective effects during the accretion phase, we find that oscillation effects are dominated by the matter-driven MSW resonances, while neutrino-neutrino collective effects contribute at the 5-10% level. The impact of the neutrino mass hierarchy, of the time-dependent neutrino spectra and of the diverse progenitor star population is 10…
In this study we include axions in stellar evolution models adopting the current stringest constraints for their coupling to photons and electrons. We obtain that the minimum stellar mass of Core Collapse Supernova (CCSN) progenitors is shifted up by nearly 2 Mo. This result seems to be in tension with the observationaly derived minimum mass of CCSN progenitors.
We use the star formation history map of the Large Magellanic Cloud recently published by Harris & Zaritsky to study the sites of the youngest Type Ia supernova remnants. We find that most Type Ia remnants are associated with old, metal-poor stellar populations, with little or no recent star formation. These include SNR 0509-67.5 which is known to have been originated by an extremely bright SN 1991T-like event, and yet is located very far away from any star forming regions. The Type Ia remnant SNR N103B, however, is associated with vigorous star formation activity in the last 100 Myr, and migh…
We investigate the red supergiant problem: the apparent dearth of Type IIP supernova progenitors with masses between 16 and 30 M_sun. Although red supergiants with masses in this range have been observed, none have been identified as progenitors in pre-explosion images. We show that by failing to take into account the additional extinction resulting from the dust produced in the red supergiant winds, we risk underestimating the luminosity of the most massive red supergiants at the end of their lives. We estimate the initial masses of all Type IIP progenitors for which observations exist and an…
The nature of the progenitor system[s] of Type Ia Supernovae is still unclear. In this contribution I review the projects that have been undertaken to answer this question and the results they have led to. The conclusion is that, as of today, we have reasonable guesses but none of them has yet been proven by direct observations.
We present a new series of supernova neutrino light curves and spectra calculated by numerical simulations for a variety of progenitor stellar masses (13-50Msolar) and metallicities (Z = 0.02 and 0.004), which would be useful for a broad range of supernova neutrino studies, e.g., simulations of future neutrino burst detection by underground detectors, or theoretical predictions for the relic supernova neutrino background. To follow the evolution from the onset of collapse to 20 s after the core bounce, we combine the results of neutrino-radiation hydrodynamic simulations for the early phase an…
Massive stars end their lives in spectacular supernova explosions. Identifying the progenitor star is a test of stellar evolution and explosion models. Here we show that the progenitor star of the supernova SN 2008bk has now disappeared, which provides conclusive evidence that this was the death of a red supergiant star.
The explosion outcome and diagnostics of core-collapse supernovae depend sensitively on the nature of the stellar progenitor, but most studies to date have focused exclusively on one-dimensional, spherically-symmetric massive star progenitors. We present some of the first core-collapse supernovae simulations of three-dimensional massive star supernovae progenitors, a 12.5- and a 15-M$_{\odot}$ model, evolved in three-dimensions from collapse to bounce through explosion with the radiation-hydrodynamic code F{\sc{ornax}}. We compare the results using those starting from three-dimensional progeni…
Justham (2011) and DiStefano et al.\ (2011) proposed that the white-dwarf progenitor of a Type Ia supernova (SN Ia) may have to spin down before it can explode. As the white dwarf spin-down timescale is not well known theoretically, we here try to constrain it empirically (within the framework of this spin-down model) for progenitor systems that contain a giant donor and for which circumbinary material has been detected after the explosion: we obtain an upper limit of a few $10^{\rm 7} {\rm yr}$. Based on the study of Di Stefano & Kilic (2012) this means that it is too early to rule out the ex…
Integral field spectroscopy of 11 type-Ib/c supernova explosion sites in nearby galaxies has been obtained using UH88/SNIFS and Gemini-N/GMOS. The use of integral field spectroscopy enables us to obtain both spatial and spectral information of the explosion site, allowing the identification of the parent stellar population of the supernova progenitor star. The spectrum of the parent population provides metallicity determination via strong-line method and age estimation obtained via comparison with simple stellar population (SSP) models. We adopt this information as the metallicity and age of t…
Although Type Ia supernovae have been heavily scrutinized due to their use in making cosmological distance estimates, we are still unable to definitively identify the progenitors for the entire population. While answers have been presented for certain specific systems, a complete solution remains elusive. We present observations of two supernova remnants (SNRs) in the Large Magellanic Cloud, SNR 0505-67.9 and SNR 0509-68.7, for which we have identified the center of the remnant and the 99.73% containment central region in which any companion star left over after the supernova must be located. …
We propose two new means of identifying the main class of progenitors of Type Ia supernovae--single or double degenerate: (i) If the range of supernova properties is significantly determined by the range of viewing angles of non-spherically symmetric explosions, then the nature of the correlation between polarization and another property (for example, the velocity gradient) can be used to determine the geometry of the asymmetry and hence the nature of the progenitor, and (ii) in the double- but not in the single-degenerate case, the range in the observed properties (e.g., velocity gradients) i…
We review all the models proposed for the progenitor systems of Type Ia supernovae and discuss the strengths and weaknesses of each scenario when confronted with observations. We show that all scenarios encounter at least a few serious diffculties, if taken to represent a comprehensive model for the progenitors of all Type Ia supernovae (SNe Ia). Consequently, we tentatively conclude that there is probably more than one channel leading SNe Ia. While the single-degenerate scenario (in which a single white dwarf accretes mass from a normal stellar companion) has been studied in some detail, the …
We infer the progenitor mass distribution for 22 historic core-collapse supernovae (CCSNe) using a Bayesian hierarchical model. For this inference, we use the local star formation histories to estimate the age for each supernova (SN). These star formation histories often show multiple bursts of star formation; our model assumes that one burst is associated with the SN progenitor and the others are random bursts of star formation. The primary inference is the progenitor age distribution. Due to the limited number of historic SNe and highly uncertain star formation at young ages, we restrict our…
We use photoionization modeling to assess the binary nature of the central stars of NGC 2392 and NGC 6026. If they are close binaries, they are potential Type Ia supernova (SN Ia) progenitors if the total mass exceeds the Chandrasekhar limit. We show that the nucleus of NGC 2392 likely has a hot, massive (\simeq 1 Ms) white dwarf companion, and a total mass of ~ 1.6 Ms, making it an especially interesting system. The binary mass in NGC 6026 is less, ~ 1.1 Ms. Even though its orbital period is short, it is not considered to be a SN Ia progenitor.
Supernovae (SNe) powered by interaction with circumstellar material provide evidence for intense stellar mass loss during the final years leading up to core collapse. We have argued that during and after core neon burning, internal gravity waves excited by core convection can tap into the core fusion power and transport a super-Eddington energy flux out to the stellar envelope, potentially unbinding up to ~ 1 solar mass of material. In this work, we explore the internal conditions of SN progenitors using the MESA 1-D stellar evolution code, in search of those most susceptible to wave-driven ma…
Luminous blue variable (LBV) stars are very massive, luminous, unstable stars that suffer frequent eruptions. In the last few years, these stars have been proposed as the direct progenitors of some core-collapse supernovae (SNe), particularly Type IIn SNe, in conflict with stellar evolution theory. In this paper we investigate various scenarios wherein LBV stars have been suggested as the immediate progenitors of SNe. Many of these suggestions stem from the fact that the SNe appear to be expanding in a high density medium, which has been interpreted as resulting from a wind with a high mass-lo…
Type IIb supernovae are believed to originate from core-collapse progenitors having kept only a very thin hydrogen envelope. We aim to explore how some physical factors, such as rotation, metallicity, overshooting, and the initial orbital period in binaries, significantly affect the Roche lobe overflow and the formation of type IIb supernovae. It is found that binaries are the main channel that capable of producing type typeIIb supernovae progenitors in the mass range for initial masses below 20 $M_{\odot}$. The formation of type IIb supernova progenitors is extremely sensitive to the initial …
We report and discuss post-explosion observations of supernova iPTF13bvn. We find that the brightness of the SN at +740 days is below the level of the pre-explosion source and thus confirm that the progenitor star has gone. We estimate that the late-time brightness is still dominated by the supernova, which constrains the magnitude and thus mass of a possible companion star to below approximately 10Msun. In turn this implies that the progenitor's initial mass is constrained to a narrow range of between 10 to 12Msun. The progenitor of iPTF13bvn would have been a helium giant rather than a Wolf-…
We present Large Binocular Telescope difference imaging data for the final years of four Type II-P/L supernovae progenitors. For all four, we find no significant evidence for stochastic or steady variability in the U, B, V, or R-bands. Our limits constrain variability to no more than roughly 5-10% of the expected R-band luminosities of the progenitors. These limits are comparable to the observed variability of red supergiants in the Magellanic Clouds. Based on these four events, the probability of a Type II-P/L progenitor having an extended outburst after Oxygen ignition is <37% at 90% confide…
This paper presents a database of the spectroscopic- and photometric- spectral energy distributions (spec-SEDs and phot-SEDs) of the progenitors of core-collapse supernovae (CCSNe). Both binary- and single-star progenitors are included in the database. The database covers the initial metallicity ($Z$) range of 0.0001--0.03, mass range of 8--25 \dsm{}, binary mass ratio range of 0--1, and orbital period range of 0.1--10000\,days. The low-resolution spec-SEDs and phot-SEDs of single- and binary-star CCSN progenitors are included in the database. These data can be used for studying the basic para…
HD 49798 is a hydrogen depleted subdwarf O6 star and has an X-ray pulsating companion (RX J0648.0-4418). The X-ray pulsating companion is a massive white dwarf. Employing Eggleton's stellar evolution code with the optically thick wind assumption, we find that the hot subdwarf HD 49798 and its X-ray pulsating companion could produce a type Ia supernova (SN Ia) in future evolution. This implies that the binary system is a likely candidate of SN Ia progenitors. We also discussed the possibilities of some other WD + He star systems (e.g. V445 Pup and KPD 1930+2752) for producing SNe Ia.
The progenitors of many type II core-collapse supernovae have now been identified directly on pre-discovery imaging. Here we present an extensive search for the progenitors of type Ibc supernovae in all available pre-discovery imaging since 1998. There are 12 type Ibc supernovae with no detections of progenitors in either deep ground-based or Hubble Space Telescope archival imaging. The deepest absolute BVR magnitude limits are between -4 and -5. We compare these limits with the observed Wolf-Rayet population in the Large Magellanic Cloud and estimate a 16 per cent probability we have failed t…
Cao et al. (2013) reported a possible progenitor detection for the type Ib supernovae iPTF13bvn for the first time. We find that the progenitor is in fact brighter than the magnitudes previously reported by approximately 0.7 to 0.2 mag with a larger error in the bluer filters. We compare our new magnitudes to our large set of binary evolution models and find that many binary models with initial masses in the range of 10 to 20M(Sun) match this new photometry and other constraints suggested from analysing the supernova. In addition these lower mass stars retain more helium at the end of the mode…
Connecting observations of core-collapse supernova explosions to the properties of their massive star progenitors is a long-sought, and challenging, goal of supernova science. Recently, Barker et al. (2022) presented bolometric light curves for a landscape of progenitors from spherically symmetric neutrino-driven core-collapse supernova (CCSN) simulations using an effective model. They find a tight relationship between the plateau luminosity of the Type II-P CCSN light curve and the terminal iron core mass of the progenitor. Remarkably, this allows us to constrain progenitor properties with ph…
Stars in the mass range from 8 to 10 solar masses are expected to produce one of two types of supernovae (SNe), either electron-capture supernovae (ECSNe) or core-collapse supernovae (CCSNe), depending on their previous evolution. Either of the associated progenitors retain extended and massive hydrogen-rich envelopes, the observables of these SNe are, therefore, expected to be similar. In this study we explore the differences in these two types of SNe. Specifically, we investigate three different progenitor models: a solar-metallicity ECSN progenitor with an initial mass of 8.8 solar masses, …
We present results of a systematic study of the mass-loss properties of Type IIn supernova progenitors within decades before their explosion. We apply an analytic light curve model to 11 Type IIn supernova bolometric light curves to derive the circumstellar medium properties. We reconstruct the mass-loss histories based on the estimated circumstellar medium properties. The estimated mass-loss rates are mostly higher than 1e-3 Msun/yr and they are consistent with those obtained by other methods. The mass-loss rates are often found to be constantly high within decades before their explosion. Thi…
The dominant radioactive energy source powering Type Ia supernova light curves is expected to switch from the decay of $^{56}$Co to $^{57}$Co at very late epochs. We use archival HST images of SN1992A obtained more than 900 days after explosion to constrain its cobalt isotopic abundance ratio and compare it to the well-studied event SN2011fe. We confirm the $^{57}$Co / $^{56}$Co ratio for SN2011fe of $0.026\pm 0.004$ found by arXiv:1608.01155, consistent with a "double degenerate" progenitor scenario. For SN1992A, we find a ratio of $0.034\pm 0.010$, but the large uncertainty does not allow us…
Core-collapse supernovae showing little or no hydrogen (denoted by Type IIb and Ib, respectively) are the explosions of massive stars that have lost some or most of their outer envelopes. How they lose their mass is unclear, but it likely involves binary interaction. So far, seven progenitors of such supernovae have been identified in pre-explosion imaging (five for Type IIb events and two for Type Ib events). Here, we evolve detailed binary stellar evolution models in order to better understand the nature of these progenitors. We find that the amount of hydrogen left in the envelope at the ti…
For typical models of binary statistics, 50-70% of core-collapse supernova (ccSN) progenitors are members of a stellar binary at the time of the explosion. Independent of any consequences of mass transfer, this has observational consequences that can be used to study the binary properties of massive stars. In particular, the secondary companion to the progenitor of a Type Ib/c SN is frequently (~50%) the more optically luminous star since the high effective temperatures of the stripped progenitors make it relatively easy for a lower luminosity, cooler secondary to emit more optical light. Seco…
We present observations of supernova (SN) 2008ge, which is spectroscopically similar to the peculiar SN 2002cx, and its pre-explosion site that indicate that its progenitor was probably a white dwarf. NGC 1527, the host galaxy of SN 2008ge, is an S0 galaxy with no evidence of star formation or massive stars. Astrometrically matching late-time imaging of SN 2008ge to pre-explosion HST imaging, we constrain the luminosity of the progenitor star. Since SN 2008ge has no indication of hydrogen or helium in its spectrum, its progenitor must have lost its outer layers before exploding, requiring that…
Red supergiants have been confirmed as the progenitor stars of the majority of hydrogen-rich type II supernovae. However, while such stars are observed with masses >25M$_\odot$, detections of >18M$_\odot$ progenitors remain elusive. Red supergiants are also expected to form at all metallicities, but discoveries of explosions from low-metallicity progenitors are scarce. Here, we report observations of the type II supernova, SN 2015bs, for which we infer a progenitor metallicity of $\leq$0.1Z$_\odot$ from comparison to photospheric-phase spectral models, and a Zero Age Main-Sequence mass of 17-2…
Type IIP supernova progenitors are often surrounded by dense circumstellar media that may result from mass-loss enhancement of the progenitors shortly before their explosions. Previous light-curve studies suggest that the mass-loss rates are enhanced up to ~ 0.1 Msun/yr, assuming a constant wind velocity. However, density of circumstellar media at the immediate stellar vicinity can be much higher than previously inferred for a given mass-loss rate if wind acceleration is taken into account. We show that the wind acceleration has a huge impact when we estimate mass-loss rates from early light c…
Over the last 15 years, the supernova community has endeavoured to identify progenitor stars of core-collapse supernovae in high resolution archival images of their galaxies.This review compiles results (from 1999 - 2013) in a distance limited sample and discusses the implications. The vast majority of the detections of progenitor stars are of type II-P, II-L or IIb with one type Ib progenitor system detected and many more upper limits for progenitors of Ibc supernovae (14). The data for these 45 supernovae progenitors illustrate a remarkable deficit of high luminosity stars above an apparent …
The progenitors of many Type II supernovae have been observationally identified but the search for Type Ibc supernova (SN Ibc) progenitors has thus far been unsuccessful, despite the expectation that they are luminous Wolf-Rayet (WR) stars. We investigate how the evolution of massive helium stars affects their visual appearances, and discuss the implications for the detectability of SN Ibc progenitors. Massive WR stars that rapidly lose their helium envelopes through stellar-wind mass-loss end their lives when their effective temperatures -- related to their hydrostatic surfaces -- exceed abou…
I summarize what we have learned about the nature of stars that ultimately explode as core-collapse supernovae from the examination of images taken prior to the explosion. By registering pre-supernova and post-supernova images, usually taken at high resolution using either space-based optical detectors, or ground-based infrared detectors equipped with laser guide star adaptive optics systems, nearly three dozen core-collapse supernovae have now had the properties of their progenitor stars either directly measured or (more commonly) constrained by establishing upper limits on their luminosities…
Theory holds that a star born with an initial mass between about 8 and 140 times the mass of the Sun will end its life through the catastrophic gravitational collapse of its iron core to a neutron star or black hole. This core collapse process is thought to usually be accompanied by the ejection of the star's envelope as a supernova. This established theory is now being tested observationally, with over three dozen core-collapse supernovae having had the properties of their progenitor stars directly measured through the examination of high-resolution images taken prior to the explosion. Here I…
We compute an extensive set of early-time spectra of supernovae interacting with circumstellar material using the radiative transfer code CMFGEN. Our models are applicable to events observed from 1 to a few days after explosion. Using these models, we constrain the progenitor and explosion properties of a sample of 17 observed interacting supernovae at early-times. Because massive stars have strong mass loss, these spectra provide valuable information about supernova progenitors, such as mass-loss rates, wind velocities, and surface abundances. We show that these events span a wide range of ex…
Thermonuclear (type Ia) supernovae are bright stellar explosions with the unique property that the light curves can be standardized, allowing them to be used as distance indicators for cosmological studies. Many fundamental questions bout these events remain, however. We provide a critique of our present understanding of these and present results of simulations assuming the single-degenerate progenitor model consisting of a white dwarf that has gained mass from a stellar companion. We present results from full three-dimensional simulations of convection with weak reactions comprising the A=23 …
In a canonical model, the progenitors of Type Ia supernovae (SNe Ia) are accreting, nuclear-burning white dwarfs (NBWDs), which explode when the white dwarf reaches the Chandrasekhar mass, M_C. Such massive NBWDs are hot (kT ~100 eV), luminous (L ~ 10^{38} erg/s), and are potentially observable as luminous supersoft X-ray sources (SSSs). During the past several years, surveys for soft X-ray sources in external galaxies have been conducted. This paper shows that the results falsify the hypothesis that a large fraction of progenitors are NBWDs which are presently observable as SSSs. The data als…
The availability of updated model atmospheres for red supergiants and improvements in single and binary stellar evolution models, as well as previously unpublished data prompted us to revisit the progenitor of low-luminosity type II-Plateau supernova, SN 2008bk. Using mid-IR data in combination with dust models, we find that high temperature (4250-4500 K), high extinction (E(B-V)>0.7) solutions are incompatible with the data. We therefore favour a cool (~3500-3700 K) progenitor with a luminosity of log(L/Lsun)~4.53. Comparing with evolutionary tracks, we infer progenitor masses in the 8-10 Msu…
We identify a pre-explosion counterpart to the nearby Type IIP supernova ASASSN-16fq (SN 2016cok) in archival Hubble Space Telescope (HST) data. The source appears to be a blend of several stars that prevents obtaining accurate photometry. However, with reasonable assumptions about the stellar temperature and extinction, the progenitor almost certainly had an initial mass M<17Msun, and was most likely in the mass range 8-12Msun. Observations once ASASSN-16fq has faded will have no difficulty accurately determining the properties of the progenitor. In 8 years of Large Binocular Telescope (LBT) …
Two "twin" Type Ia supernovae (SNe Ia), SNe 2011by and 2011fe, have extremely similar optical light-curve shapes, colors, and spectra, yet have different ultraviolet (UV) continua as measured in Hubble Space Telescope spectra and measurably different peak luminosities. We attribute the difference in the UV continua to significantly different progenitor metallicities. This is the first robust detection of different metallicities for SN Ia progenitors. Theoretical reasoning suggests that differences in metallicity also lead to differences in luminosity. SNe Ia with higher progenitor metallicitie…
The progenitors of Type IIP supernovae (SNe) are known to be red supergiants, but their properties are not well determined. We employ hydrodynamical modelling to investigate the explosion characteristics of eight Type IIP supernovae, and the properties of their progenitor stars. We create evolutionary models using the {\sc MESA} stellar evolution code, explode these models, and simulate the optical lightcurves using the {\sc STELLA} code. We fit the optical lightcurves, Fe II 5169Å velocity, and photospheric velocity, to the observational data. Recent research has suggested that the progenitor…
We explore a new scenario for producing stripped-envelope supernova progenitors. In our scenario, the stripped-envelope supernova is the second supernova of the binary, in which the envelope of the secondary was removed during its red supergiant phase by the impact of the first supernova. Through 2D hydrodynamical simulations, we find that $\sim$50-90$\%$ of the envelope can be unbound as long as the pre-supernova orbital separation is $\lesssim5$ times the stellar radius. Recombination energy plays a significant role in the unbinding, especially for relatively high mass systems ($\gtrsim18M_\…
Type Ibn supernovae (SNe) are a rare class of stellar explosions whose progenitor systems are not yet well determined. We present and analyze observations of the Type Ibn SN 2019kbj, and model its light curve in order to constrain its progenitor and explosion parameters. SN 2019kbj shows roughly constant temperature during the first month after peak, indicating a power source (likely circumstellar material interaction) that keeps the continuum emission hot at ~15,000K. Indeed, we find that the radioactive decay of Ni56 is disfavored as the sole power source of the bolometric light curve. A rad…
The creation of "hybrid" white dwarfs, made of a C-O core within a O-Ne shell has been proposed, and studies indicate that ignition in the C-rich central region makes these viable progenitors for thermonuclear (type Ia) supernovae. Recent work found that the C-O core is mixed with the surrounding O-Ne as the white dwarf cools prior to accretion, which results in lower central C fractions in the massive progenitor than previously assumed. To further investigate the efficacy of hybrid white dwarfs as progenitors of thermonuclear supernovae, we performed simulations of thermonuclear supernovae fr…
Despite the significance of Type Ia supernovae (SNeIa) in many fields in astrophysics, SNeIa lack a theoretical explanation. The standard scenarios involve thermonuclear explosions of carbon/oxygen white dwarfs approaching the Chandrasekhar mass; either by accretion from a companion or by a merger of two white dwarfs. We investigate the contribution from both channels to the SNIa rate with the binary population synthesis (BPS) code SeBa in order to constrain binary processes such as the mass retention efficiency of WD accretion and common envelope evolution. We determine the theoretical rates …
