scholarly journals Supernova Abundance Generation

1991 ◽  
Vol 145 ◽  
pp. 21-38
Author(s):  
K. Nomoto ◽  
T. Shigeyama ◽  
T. Tsujimoto
Keyword(s):  
Heavy Element ◽  
Massive Stars ◽  
Theoretical Models ◽  
Light Curves ◽  
Maximum Brightness ◽  
Sn 1987A ◽  
New Models ◽  
Decline Rate ◽  
Type Ia ◽  
Supernova Explosions

Theoretical models of supernova explosions of various types are reviewed to obtain heavy element yields from supernovae. We focus on new models for SN 1987A, and Type Ia, Ib, and Ic supernovae. Maximum brightness and decline rate of their light curves suggest that 12–18 M⊙ stars produce larger amount of 56Ni than more massive stars. We discuss relative roles of various types of supernovae in the chemical evolution of galaxies.

scholarly journals Theoretical Light Curves for Type Ia Supernovae and Determination of the Hubble Constant

1999 ◽  
Vol 183 ◽  
pp. 68-68
Author(s):  
Koichi Iwamoto ◽  
Ken'Ichi Nomoto
Keyword(s):  
Hubble Constant ◽  
Light Curves ◽  
Type Ia Supernovae ◽  
Maximum Brightness ◽  
Decline Rate ◽  
Type Ia ◽  
Error Bars ◽  
Ia Supernovae ◽  
Distance Indicators

The large luminosity (MV ≈ −19 ∼ −20) and the homogeneity in light curves and spectra of Type Ia supernovae(SNe Ia) have led to their use as distance indicators ultimately to determine the Hubble constant (H0). However, an increasing number of the observed samples from intermediate- and high-z (z ∼ 0.1 − 1) SN Ia survey projects(Hamuy et al. 1996, Perlmutter et al. 1997) have shown that there is a significant dispersion in the maximum brightness (∼ 0.4 mag) and the brighter-slower correlation between the brightness and the postmaximum decline rate, which was first pointed out by Phillips(1993). By taking the correlation into account, Hamuy et al.(1996) gave an estimate of H0 within the error bars half as much as previous ones.

scholarly journals Linear spectropolarimetry of 35 Type Ia supernovae with VLT/FORS: an analysis of the Si ii line polarization

2019 ◽  
Vol 490 (1) ◽  
pp. 578-599 ◽  
Author(s):  
Aleksandar Cikota ◽  
Ferdinando Patat ◽  
Lifan Wang ◽  
J Craig Wheeler ◽  
Mattia Bulla ◽  
...  
Keyword(s):  
Type Ia Supernovae ◽  
Maximum Brightness ◽  
Numerical Predictions ◽  
Very Large Telescope ◽  
Type Ia ◽  
Supernova Explosions ◽  
Statistical Sample ◽  
Ia Supernovae ◽  
Low Dispersion ◽  
Detonation Model

ABSTRACT Spectropolarimetry enables us to measure the geometry and chemical structure of the ejecta in supernova explosions, which is fundamental for the understanding of their explosion mechanism(s) and progenitor systems. We collected archival data of 35 Type Ia supernovae (SNe Ia), observed with Focal Reducer and Low-Dispersion Spectrograph (FORS) on the Very Large Telescope at 127 epochs in total. We examined the polarization of the Si ii λ6355 Å line ($p_{\rm Si\, \small {II}}$) as a function of time, which is seen to peak at a range of various polarization degrees and epochs relative to maximum brightness. We reproduced the $\Delta m_{15}\!-\!p_{\rm Si\, \small {II}}$ relationship identified in a previous study, and show that subluminous and transitional objects display polarization values below the $\Delta m_{15}\!-\!p_{\rm Si\, \small {II}}$ relationship for normal SNe Ia. We found a statistically significant linear relationship between the polarization of the Si ii λ6355 Å line before maximum brightness and the Si ii line velocity and suggest that this, along with the $\Delta m_{15}\!-\!p_{\rm Si\, \small {II}}$ relationship, may be explained in the context of a delayed-detonation model. In contrast, we compared our observations to numerical predictions in the $\Delta m_{15}\!-\!v_{\rm Si\, \small {II}}$ plane and found a dichotomy in the polarization properties between Chandrasekhar and sub-Chandrasekhar mass explosions, which supports the possibility of two distinct explosion mechanisms. A subsample of SNe displays evolution of loops in the q–u plane that suggests a more complex Si structure with depth. This insight, which could not be gleaned from total flux spectra, presents a new constraint on explosion models. Finally, we compared our statistical sample of the Si ii polarization to quantitative predictions of the polarization levels for the double-detonation, delayed-detonation, and violent-merger models.

scholarly journals Iron-peak elements Sc, V, Mn, Cu, and Zn in Galactic bulge globular clusters

2018 ◽  
Vol 616 ◽  
pp. A18 ◽  
Author(s):  
H. Ernandes ◽  
B. Barbuy ◽  
A. Alves-Brito ◽  
A. Friaça ◽  
C. Siqueira-Mello ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Massive Stars ◽  
Theoretical Models ◽  
Thick Disk ◽  
Galactic Bulge ◽  
Abundance Pattern ◽  
Chemical Enrichment ◽  
Very Large Telescope ◽  
Type Ia ◽  
Cu And Zn

Aims. Globular clusters are tracers of the history of star formation and chemical enrichment in the early Galaxy. Their abundance pattern can help understanding their chemical enrichment processes. In particular, the iron-peak elements have been relatively little studied so far in the Galactic bulge. Methods. The main aim of this work is to verify the strength of abundances of iron-peak elements for chemical tagging in view of identifying different stellar populations. Besides, the nucleosynthesis processes that build these elements are complex, therefore observational data can help constraining theoretical models, as well as give suggestions as to the kinds of supernovae that enriched the gas before these stars formed. Results. The abundances of iron-peak elements are derived for the sample clusters, and compared with bulge field, and thick disk stars. We derived abundances of the iron-peak elements Sc, V, Mn, Cu, and Zn in individual stars of five bulge globular clusters (NGC 6528, NGC 6553, NGC 6522, NGC 6558, HP 1), and of the reference thick disk/or inner halo cluster 47 Tucanae (NGC 104). High resolution spectra were obtained with the UVES spectrograph at the Very Large Telescope over the years. Conclusions. The sample globular clusters studied span metallicities in the range –1.2 ≲ [Fe/H] ≲ 0.0. V and Sc appear to vary in lockstep with Fe, indicating that they are produced in the same supernovae as Fe. We find that Mn is deficient in metal-poor stars, confirming that it is underproduced in massive stars; Mn-over-Fe steadily increases at the higher metallicities due to a metallicity-dependent enrichment by supernovae of type Ia. Cu behaves as a secondary element, indicating its production in a weak-s process in massive stars. Zn has an alpha-like behaviour at low metallicities, which can be explained in terms of nucleosynthesis in hypernovae. At the metal-rich end, Zn decreases with increasing metallicity, similarly to the alpha-elements.

scholarly journals Explosions of Helium Stars and Type IB/IC/IIB Supernovae

1991 ◽  
Vol 143 ◽  
pp. 515-528 ◽  
Author(s):  
K. Nomoto
Keyword(s):  
Binary Systems ◽  
Theoretical Models ◽  
Light Curves ◽  
Close Binary ◽  
Star Models ◽  
Helium Stars ◽  
Fast Decline ◽  
Supernova Explosions ◽  
Low Mass ◽  
Helium Star

Theoretical models of supernova explosions of helium stars with various masses are reviewed to examine possible connections between Wolf-Rayet stars and Type Ib/Ic/IIb supernovae. Nucleosynthesis, Rayleigh-Taylor instabilities, and light curves are compared with observations. Maximum brightness and the fast decline of the light curves of typical SNe Ib/Ic can be well accounted for by the helium star models if the helium star mass is as low as 3-5 M⊙. These low mass helium stars can form from stars of 12-18 M⊙ after Roche-lobe overflow in close binary systems. Probably progenitors of typical SNe Ib/Ic are not classified as Wolf-Rayet stars.

scholarly journals SN 2015bq: A Luminous Type Ia Supernova with Early Flux Excess

2022 ◽  
Vol 924 (1) ◽  
pp. 35
Author(s):  
Liping Li ◽  
Jujia Zhang ◽  
Benzhong Dai ◽  
Wenxiong Li ◽  
Xiaofeng Wang ◽  
...  
Keyword(s):  
Radioactive Decay ◽  
Absolute Magnitude ◽  
Light Curves ◽  
Iron Group ◽  
Intermediate Mass ◽  
Bolometric Luminosity ◽  
Type Ia Supernova ◽  
Decline Rate ◽  
Type Ia ◽  
Absorption Features

Abstract We present optical and ultraviolet (UV) observations of a luminous type Ia supernova (SN Ia) SN 2015bq characterized by early flux excess. This SN reaches a B-band absolute magnitude at M B = −19.68 ± 0.41 mag and a peak bolometric luminosity at L = (1.75 ± 0.37) × 1043 erg s−1, with a relatively small post-maximum decline rate [Δm 15(B) = 0.82 ± 0.05 mag]. The flux excess observed in the light curves of SN 2015bq a few days after the explosion, especially seen in the UV bands, might be due to the radioactive decay of 56Ni mixed into the surface. The radiation from the decay of the surface 56Ni heats the outer layer of this SN. It produces blue U − B color followed by monotonically reddening in the early phase, dominated iron-group lines, and weak intermediate-mass element absorption features in the early spectra. The scenario of enhanced 56Ni in the surface is consistent with a large amount of 56Ni ( M 56 Ni = 0.97 ± 0.20 M ☉) synthesized during the explosion. The properties of SN 2015bq are found to locate between SN 1991T and SN 1999aa, suggesting the latter two subclasses of SNe Ia may have a common origin.

Spectropolarimetric Diagnostics of Thermonuclear Supernova Explosions

Science ◽  
2006 ◽  
Vol 315 (5809) ◽  
pp. 212-214 ◽  
Author(s):  
Lifan Wang ◽  
Dietrich Baade ◽  
Ferdinando Patat
Keyword(s):  
Light Curve ◽  
Outer Layer ◽  
Statistical Study ◽  
Strong Support ◽  
Type Ia Supernovae ◽  
Geometric Structures ◽  
Decline Rate ◽  
Type Ia ◽  
Supernova Explosions ◽  
Ia Supernovae

Even at extragalactic distances, the shape of supernova ejecta can be effectively diagnosed by spectropolarimetry. We present results for 17 type Ia supernovae that allow a statistical study of the correlation among the geometric structures and other observable parameters of type Ia supernovae. These observations suggest that type Ia supernova ejecta typically consist of a smooth, central, iron-rich core and an outer layer with chemical asymmetries. The degree of this peripheral asphericity is correlated with the light-curve decline rate of type Ia supernovae. These results lend strong support to delayed-detonation models of type Ia supernovae.

scholarly journals Two transitional type Ia supernovae located in the Fornax cluster member NGC 1404: SN 2007on and SN 2011iv

2018 ◽  
Vol 611 ◽  
pp. A58 ◽  
Author(s):  
C. Gall ◽  
M. D. Stritzinger ◽  
C. Ashall ◽  
E. Baron ◽  
C. R. Burns ◽  
...  
Keyword(s):  
Near Infrared ◽  
Transition Density ◽  
Light Curves ◽  
Central Density ◽  
Type Ia Supernovae ◽  
Cluster Member ◽  
Decline Rate ◽  
Type Ia ◽  
Ia Supernovae ◽  
Fornax Cluster

We present an analysis of ultraviolet (UV) to near-infrared observations of the fast-declining Type Ia supernovae (SNe Ia) 2007on and 2011iv, hosted by the Fornax cluster member NGC 1404. The B-band light curves of SN 2007on and SN 2011iv are characterised by Δm15 (B) decline-rate values of 1.96 mag and 1.77 mag, respectively. Although they have similar decline rates, their peak B- and H-band magnitudes differ by ~ 0.60 mag and ~0.35 mag, respectively. After correcting for the luminosity vs. decline rate and the luminosity vs. colour relations, the peak B-band and H-band light curves provide distances that differ by ~ 14% and ~ 9%, respectively. These findings serve as a cautionary tale for the use of transitional SNe Ia located in early-type hosts in the quest to measure cosmological parameters. Interestingly, even though SN 2011iv is brighter and bluer at early times, by three weeks past maximum and extending over several months, its B − V colour is 0.12 mag redder than that of SN 2007on. To reconcile this unusual behaviour, we turn to guidance from a suite of spherical one-dimensional Chandrasekhar-mass delayed-detonation explosion models. In this context, 56Ni production depends on both the so-called transition density and the central density of the progenitor white dwarf. To first order, the transition density drives the luminosity–width relation, while the central density is an important second-order parameter. Within this context, the differences in the B − V colour evolution along the Lira regime suggest that the progenitor of SN 2011iv had a higher central density than SN 2007on.

scholarly journals The Half-Life of Titanium 44 and SN 1987A

1998 ◽  
Vol 188 ◽  
pp. 241-242
Author(s):  
Yuko S. Mochizuki ◽  
Shiomi Kumagai
Keyword(s):  
Coming Out ◽  
Half Life ◽  
Gamma Ray ◽  
Light Curves ◽  
Radioactive Isotopes ◽  
Sn 1987A ◽  
Large Spread ◽  
Decay Sequence ◽  
Supernova Explosions ◽  
Strong Candidate

The radioactive isotopes, such as 44Ti and 56Ni, are synthesized as a result of rapid nucleosynthesis in supernova explosions. The gamma-ray photons coming out from the decay sequence of 44Ti is now a strong candidate to explain the the late light curve of SN 1987A. It is noted here that the energy release from the 44Ti decay depends strongly on its half-life. However, the published values for 44Ti half-life display a large spread, ranging from ~ 35 to ~ 68 years. In this paper (Kumagai et al. 1997; see also Kumagai et al. 1993), we discuss the value of the half-life by comparing the theoretical light curves and the observations in SN 1987A. The unestablished half-life value is related to the ratio of the abundance of 44Ti to that of 56Ni.

scholarly journals Evolution & Explosion of Massive Stars Leading to IIP-IIL SNe with MESA & SNEC

2017 ◽  
Vol 12 (S331) ◽  
pp. 11-16 ◽  
Author(s):  
Sanskriti Das ◽  
Alak Ray
Keyword(s):  
Mass Loss ◽  
Massive Stars ◽  
Light Curves ◽  
Explosion Energy ◽  
Type Ii ◽  
Decline Rate ◽  
Circumstellar Gas ◽  
Red Supergiants

AbstractWe show how the dense shells of circumstellar gas immediately outside the red supergiants(RSGs) can affect the early optical light curves of Type II-P SNe taking the example of 2013ej. The peak in V, R and I bands, decline rate after peak and plateau length are found to be strongly influenced by the dense CSM formed due to enhanced mass loss during the oxygen and silicon burning stage of the progenitor. We find that the required explosion energy for the progenitors with CSM is reduced by almost a factor of 2.

scholarly journals Near-Infrared Properties of Type Ia Supernovae

2012 ◽  
Vol 29 (4) ◽  
pp. 434-446 ◽  
Author(s):  
M. M. Phillips
Keyword(s):  
Near Infrared ◽  
Light Curves ◽  
Type Ia Supernovae ◽  
Decline Rate ◽  
Type Ia ◽  
Ia Supernovae ◽  
Peak Luminosity

AbstractThe photometric properties of Type Ia supernovae (SNe Ia) in the near-infrared as garnered from observations made over the last 30 years are reviewed. During this period, light curves for more than 120 nearby SNe Ia have been published, revealing considerable homogeneity but also some fascinating differences. These data have confirmed that, for all but the fastest declining objects, SNe Ia are essentially perfect standard candles in the near-infrared, displaying only a slight dependence of peak luminosity on decline rate and color.

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