On the possibility of systematizing classical novae by light curve type. II. Observational characteristics of novae and groups

Astrophysics ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 140-148 ◽  
Author(s):  
A. E. Rosenbush
Keyword(s):  
Light Curve ◽  
Type Ii ◽  
Classical Novae ◽  
Curve Type

scholarly journals Progenitors and Hydrodynamics of Type II and lb Supernovae

1996 ◽  
Vol 145 ◽  
pp. 137-147
Author(s):  
S. E. Woosley ◽  
T. A. Weaver ◽  
R. G. Eastman
Keyword(s):  
Black Holes ◽  
Light Curve ◽  
Mass Loss ◽  
Massive Stars ◽  
The Other ◽  
Shock Interaction ◽  
Type Ii ◽  
Residual Hydrogen ◽  
Ordinary Type ◽  
The One

We review critical physics affecting the observational characteristics of those supernovae that occur in massive stars. Particular emphasis is given to 1) how mass loss, either to a binary companion or by a radiatively driven wind, affects the type and light curve of the supernova, and 2) the interaction of the outgoing supernova shock with regions of increasing pr3 in the stellar mantle. One conclusion is that Type II-L supernovae may occur in mass exchanging binaries very similar to the one that produced SN 1993J, but with slightly larger initial separations and residual hydrogen envelopes (∼1 Mʘ and radius ∼ several AU). The shock interaction, on the other hand, has important implications for the formation of black holes in explosions that are, near peak light, observationally indistinguishable from ordinary Type II-p and lb supernovae.

scholarly journals SN 2017ivv: two years of evolution of a transitional Type II supernova

2020 ◽  
Vol 499 (1) ◽  
pp. 974-992
Author(s):  
C P Gutiérrez ◽  
A Pastorello ◽  
A Jerkstrand ◽  
L Galbany ◽  
M Sullivan ◽  
...  
Keyword(s):  
Light Curve ◽  
Main Sequence ◽  
Rapid Decline ◽  
Type Ii ◽  
Additional Energy ◽  
V Band ◽  
Weak Phase ◽  
Faint Galaxy ◽  
Transitional Type ◽  
Fast Rise

ABSTRACT We present the photometric and spectroscopic evolution of the Type II supernova (SN II) SN 2017ivv (also known as ASASSN-17qp). Located in an extremely faint galaxy (Mr = −10.3 mag), SN 2017ivv shows an unprecedented evolution during the 2 yr of observations. At early times, the light curve shows a fast rise (∼6−8 d) to a peak of ${\it M}^{\rm max}_{g}= -17.84$ mag, followed by a very rapid decline of 7.94 ± 0.48 mag per 100 d in the V band. The extensive photometric coverage at late phases shows that the radioactive tail has two slopes, one steeper than that expected from the decay of 56Co (between 100 and 350 d), and another slower (after 450 d), probably produced by an additional energy source. From the bolometric light curve, we estimated that the amount of ejected 56Ni is ∼0.059 ± 0.003 M⊙. The nebular spectra of SN 2017ivv show a remarkable transformation that allows the evolution to be split into three phases: (1) Hα strong phase (<200 d); (2) Hα weak phase (between 200 and 350 d); and (3) Hα broad phase (>500 d). We find that the nebular analysis favours a binary progenitor and an asymmetric explosion. Finally, comparing the nebular spectra of SN 2017ivv to models suggests a progenitor with a zero-age main-sequence mass of 15–17 M⊙.

scholarly journals Supernovae from blue supergiant progenitors: What a mess!

2019 ◽  
Vol 622 ◽  
pp. A70 ◽  
Author(s):  
Luc Dessart ◽  
D. John Hillier
Keyword(s):  
Light Curve ◽  
Line Width ◽  
Spectroscopic Properties ◽  
Blue Color ◽  
Type Ii ◽  
Spectral Evolution ◽  
Sn 1987A ◽  
Rich Diversity ◽  
Alternative Power ◽  
Low Metallicity

Supernova (SN) 1987A was classified as a peculiar Type II SN because of its long rising light curve and the persistent presence of H I lines in optical spectra. It was subsequently realized that its progenitor was a blue supergiant (BSG), rather than a red supergiant (RSG) as for normal, Type II-P, SNe. Since then, the number of Type II-pec SNe has grown, revealing a rich diversity in photometric and spectroscopic properties. In this study, using a single 15 M⊙ low-metallicity progenitor that dies as a BSG, we have generated explosions with a range of energies and 56Ni masses. We then performed the radiative transfer modeling with CMFGEN, from 1 d until 300 d after explosion for all ejecta. Our models yield light curves that rise to optical maximum in about 100 d, with a similar brightening rate, and with a peak absolute V-band magnitude spanning −14 to −16.5 mag. All models follow a similar color evolution, entering the recombination phase within a few days of explosion, and reddening further until the nebular phase. Their spectral evolution is analogous, mostly differing in line width. With this model set, we study the Type II-pec SNe 1987A, 2000cb, 2006V, 2006au, 2009E, and 2009mw. The photometric and spectroscopic diversity of observed SNe II-pec suggests that there is no prototype for this class. All these SNe brighten to maximum faster than our limited set of models, except perhaps SN 2009mw. The spectral evolution of SN 1987A conflicts with other observations in this set and conflicts with model predictions from 20 d until maximum: Hα narrows and weakens while Ba II lines strengthen faster than expected, which we interpret as signatures of clumping. SN 2000cb rises to maximum in only 20 d and shows weak Ba II lines. Its spectral evolution (color, line width and strength) is well matched by an energetic ejecta but the light curve may require strong asymmetry. The persistent blue color, narrow lines, and weak Hα absorption, seen in SN 2006V conflicts with expectations for a BSG explosion powered by 56Ni and may require an alternative power source. In contrast with theoretical expectations, observed spectra reveal a diverse behavior for lines like Ba II 6142 Å, Na I D, and Hα. In addition to diversity arising from different BSG progenitors, we surmise that their ejecta are asymmetric, clumped, and, in some cases, not solely powered by 56Ni decay.

scholarly journals Super-luminous Type II supernovae powered by magnetars

2018 ◽  
Vol 613 ◽  
pp. A5 ◽  
Author(s):  
Luc Dessart ◽  
Edouard Audit
Keyword(s):  
Light Curve ◽  
Spectroscopic Properties ◽  
Radiation Hydrodynamics ◽  
Equal Proportion ◽  
Type Ii ◽  
Standard Type ◽  
Fluid Instabilities ◽  
Dense Shell ◽  
Standard Energy ◽  
Photospheric Temperature

Magnetar power is believed to be at the origin of numerous super-luminous supernovae (SNe) of Type Ic, arising from compact, hydrogen-deficient, Wolf-Rayet type stars. Here, we investigate the properties that magnetar power would have on standard-energy SNe associated with 15–20 M⊙ supergiant stars, either red (RSG; extended) or blue (BSG; more compact). We have used a combination of Eulerian gray radiation-hydrodynamics and non-LTE steady-state radiative transfer to study their dynamical, photometric, and spectroscopic properties. Adopting magnetar fields of 1, 3.5, 7 × 1014 G and rotational energies of 0.4, 1, and 3 × 1051 erg, we produce bolometric light curves with a broad maximum covering 50–150 d and a magnitude of 1043–1044 erg s−1. The spectra at maximum light are analogous to those of standard SNe II-P but bluer. Although the magnetar energy is channelled in equal proportion between SN kinetic energy and SN luminosity, the latter may be boosted by a factor of 10–100 compared to a standard SN II. This influence breaks the observed relation between brightness and ejecta expansion rate of standard Type II SNe. Magnetar energy injection also delays recombination and may even cause re-ionization, with a reversal in photospheric temperature and velocity. Depositing the magnetar energy in a narrow mass shell at the ejecta base leads to the formation of a dense shell at a few 1000 km s−1, which causes a light-curve bump at the end of the photospheric phase. Depositing this energy over a broad range of mass in the inner ejecta, to mimic the effect of multi-dimensional fluid instabilities, prevents the formation of a dense shell and produces an earlier-rising and smoother light curve. The magnetar influence on the SN radiation is generally not visible prior to 20–30 d, during which one may discern a BSG from a RSG progenitor. We propose a magnetar model for the super-luminous Type II SN OGLE-SN14-073.

SN 1987a: A Progress Report

1987 ◽  
Vol 7 (2) ◽  
pp. 141-146 ◽  
Author(s):  
M. A. Dopita ◽  
N. Achilleos ◽  
J. A. Dawe ◽  
C. Flynn ◽  
S. J. Meatheringham ◽  
...  
Keyword(s):  
Light Curve ◽  
Thermal Energy ◽  
Radioactive Decay ◽  
Progress Report ◽  
Type Ii ◽  
Normal Type ◽  
Spectral Evolution ◽  
Core Mass ◽  
Sn 1987A ◽  
Residual Hydrogen

AbstractIt now appears almost certain that the precursor of SN 1987a was the brighter of the components of Sk-69 202, a blue supergiant, with a precursor mass of perhaps 12-16 solar masses. Prior to the explosion the precursor had a core mass of order six solar masses, and 0.1 to 0.2 solar masses of residual hydrogen envelope. The compact nature of this star can account for many of the odd features of the subsequent light curve and spectral evolution.An analysis of the light curve and colour evolution shows four distinct epochs, which probably relate to the initial expansion of the fireball and the escape of shock-deposited thermal energy, the hydrogen-rich layers becoming optically thin, the exposure of the helium core, and the increasing transparency of the helium core.The supernova appeared to be at its maximum on May 10, but is dimmer than a normal Type II because its light is apparently derived from recombinations and the radioactive decay of 56Ni to 56Co to 56Fe rather than by the thermal energy deposited by the passage of the shock.

scholarly journals Optical Observations of Recent Novae

1977 ◽  
Vol 42 ◽  
pp. 149-181
Author(s):  
B. Wolf
Keyword(s):  
Light Curve ◽  
Absolute Magnitude ◽  
Optical Observations ◽  
Variable Amplitude ◽  
Classical Novae ◽  
Binary Nature ◽  
M 10 ◽  
Speed Of Evolution

AbstractThe observations of two rather different classical novae, V 1500 Cyg (= Nova Cyg 1975) and NQ Vul (= Nova Vul 1976), are presented and compared. Nova Cyg 1975 is outstanding with respect to absolute magnitude (M = -10), range of brightening (Δm = 19), and speed of evolution (t3= 3.6 days). Its prenova object had to be fainter than about magnitude 9. The corresponding values for Nova Vul 1976 are rather conservative (M≈-7.5, Δm ≈ 12, t3=40 days, absolute magnitude of the prenova ≈4.5). The light curve of Nova Cyg 1975 is very smooth. Some superimposed photometric variations of a small and slightly variable amplitude of a period of 3.4 hours are most naturally ascribed to a binary nature of Nova Cyg 1975. Nova Vul 1976 has a completely different lighteurve with extremely strong rapid irregular variations of considerably amplitude. There is a remarkable second maximum about 14 days after discovery.

scholarly journals Expected Changes of SNe with Redshift due to Evolution of Their Progenitors

2005 ◽  
Vol 192 ◽  
pp. 567-572
Author(s):  
Inma Domínguez ◽  
Peter Höflich ◽  
Oscar Straniero ◽  
Marco Limongi ◽  
Alessandro Chieffi
Keyword(s):  
Light Curve ◽  
Main Sequence ◽  
High Redshift ◽  
Stellar Populations ◽  
Light Curves ◽  
Type Ii ◽  
First Stars ◽  
Metal Free ◽  
Standard Candle ◽  
Type Ia

SummaryWe have analyzed the influence of the stellar populations, from which SN progenitors come, on the observational outcome, including the metal free Pop. III. We use our models to study the evolution of the progenitor, the subsequent explosion and the light curves. For Type Ia, the variation of the main sequence mass of the progenitor of the exploding WD produces an offset in the maximum-decline relation of 0.2 mag. This effect is critical for the use of high redshift Type Ia SNe as cosmological standard candles. In contrast, the metallicity does not change the above relation (at maximum, ΔMV ≤0.06 mag). For Type II, we find a dependence of the light curve properties with both main sequence mass and metallicity of the progenitor, and we identify a rather homogeneous subclass, “Extreme II-P,” that may be used as a quasi-standard candle. Note that, although not as good as Type Ia for distance determinations, Type II are expected to have occurred since the first stars were formed.

scholarly journals Influence of macroclumping on type II supernova light curves

2019 ◽  
Vol 629 ◽  
pp. A17
Author(s):  
Luc Dessart ◽  
Edouard Audit
Keyword(s):  
Light Curve ◽  
Early Time ◽  
Radiation Energy ◽  
Mean Free Path ◽  
Light Curves ◽  
Type Ii ◽  
Different Temperatures ◽  
Curve Modeling ◽  
2D And 3D ◽  
The Impact

Core-collapse supernova (SN) ejecta are probably structured on both small and large scales, with greater deviations from spherical symmetry nearer the explosion site. Here, we present 2D and 3D gray radiation hydrodynamics simulations of type II SN light curves from red and blue supergiant star explosions to investigate the impact of inhomogeneities in density or composition on SN observables, with a characteristic scale set to a few percent of the local radius. Clumping is found to hasten the release of stored radiation, boosting the early time luminosity and shortening the photospheric phase. Around the photosphere, radiation leaks between the clumps where the photon mean free path is greater. Since radiation is stored uniformly in volume, a greater clumping can increase this leakage by storing more and more mass into smaller and denser clumps containing less and less radiation energy. An inhomogeneous medium in which different regions recombine at different temperatures can also impact the light curve. Clumping can thus be a source of diversity in SN brightness. Clumping may lead to a systematic underestimate of ejecta masses from light curve modeling, although a significant offset seems to require a large density contrast of a few tens between clumps and interclump medium.

scholarly journals SN 2016gsd: an unusually luminous and linear Type II supernova with high velocities

2020 ◽  
Vol 493 (2) ◽  
pp. 1761-1781 ◽  
Author(s):  
T M Reynolds ◽  
M Fraser ◽  
S Mattila ◽  
M Ergon ◽  
L Dessart ◽  
...  
Keyword(s):  
Light Curve ◽  
Massive Star ◽  
Absolute Magnitude ◽  
Host Galaxy ◽  
Type Ii ◽  
High Luminosity ◽  
Linear Type ◽  
Circumstellar Material ◽  
Low Metallicity ◽  
Edge Tracing

ABSTRACT We present observations of the unusually luminous Type II supernova (SN) 2016gsd. With a peak absolute magnitude of V = −19.95 ± 0.08, this object is one of the brightest Type II SNe, and lies in the gap of magnitudes between the majority of Type II SNe and the superluminous SNe. Its light curve shows little evidence of the expected drop from the optically thick phase to the radioactively powered tail. The velocities derived from the absorption in H α are also unusually high with the blue edge tracing the fastest moving gas initially at 20 000 km s−1, and then declining approximately linearly to 15 000 km s−1 over ∼100 d. The dwarf host galaxy of the SN indicates a low-metallicity progenitor which may also contribute to the weakness of the metal lines in its spectra. We examine SN 2016gsd with reference to similarly luminous, linear Type II SNe such as SNe 1979C and 1998S, and discuss the interpretation of its observational characteristics. We compare the observations with a model produced by the jekyll code and find that a massive star with a depleted and inflated hydrogen envelope struggles to reproduce the high luminosity and extreme linearity of SN 2016gsd. Instead, we suggest that the influence of interaction between the SN ejecta and circumstellar material can explain the majority of the observed properties of the SN. The high velocities and strong H α absorption present throughout the evolution of the SN may imply a circumstellar medium configured in an asymmetric geometry.

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