PISN 2018ibb: radioactive emission of [O III] lines

Nikolai N. Chugai

REVIEW 3 major objections 6 minor 9 references

PISN 2018ibb: radioactive emission of [O III] lines

T0 review · 3 major / 6 minor · reviewed 2026-08-10 · deepseek-v4-flash

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Pith's one-line read With macroscopic mixing of nickel and oxygen, $^{56}$Co decay can power the strong [O III] lines of SN 2018ibb, so circumstellar interaction is not required.

desk verdict A short, honest one-zone model makes a plausible case that 56Co decay, given macroscopic mixing, can power the [O III] emission in SN 2018ibb, but the central luminosity match is a fit to Te and chi, and the two-zone discrepancies are acknowledged; the scaling relation is the cleanest result. read the letter →

arxiv 2501.07134 v1 pith:45DLIMMM submitted 2025-01-13 astro-ph.HE astro-ph.SR

Nikolai N. Chugai This is my paper · ORCID

classification astro-ph.HEastro-ph.SR

keywords SN2018ibbpair-instabilitysupernovae[OIII]emissionradioactiveenergydeposition56Codecaymacroscopicmixingnebularphasesuperluminous

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper asks whether the strong [O III] 5007, 4959, and 4363 Å emission of the pair-instability supernova SN 2018ibb, at roughly $10^{41}$ erg s$^{-1}$, can be produced by radioactive heating alone. Its answer is yes, provided the ejecta contain macroscopic mixing between $^{56}$Ni and oxygen: gamma-rays from $^{56}$Co decay deposit energy directly into oxygen matter, ionizing and exciting O III. A one-zone model with realistic ejecta mass, energy, and $^{56}$Ni mass reproduces the observed line luminosity and temperature-sensitive flux ratios for an oxygen mass of 10–15 $M_\odot$, a temperature near 9000 K, and a density contrast $\chi \approx 2$–3. The paper also derives a scaling relation $y_3 \propto M_{\mathrm{Ni}}^{3/2} M^{-7/2}$ that explains why the [O III]/[O I] ratio should vary widely among pair-instability supernovae.

What carries the argument

The central object is a one-zone, free-expansion model of the ejecta with mass $M = 60\,M_\odot$, energy $E = 1.2 \times 10^{52}$ erg, and $M_{\mathrm{Ni}} = 30\,M_\odot$, in which oxygen occupies a filling factor $f = (M_O/M)\chi^{-1}$ with density contrast $\chi$. The key condition is $\Delta\tau_\gamma = \delta k_\gamma \rho v_0 t \approx 2.2\delta < 1$, meaning gamma-rays from $^{56}$Co cross oxygen without strong absorption, so the deposited power in oxygen is $L_d(O) = (M_O/M)L$. Ionization balance is solved in steady state, and line emissivities come from three-level balance equations with radiative and collisional transitions. The argument is carried by the scaling $y_3 \propto M_{\mathrm{Ni}}^{3/2} M^{-7/2}$, derived from the O II–O III ionization balance combined with the relation $M_{\mathrm{Ni}} \propto E^3$; this scaling translates ejecta mass and nickel mass into the O III fraction and therefore into the [O III]/[O I] line ratio.

What would settle it

Monitor the [O III] 5007 luminosity at late times, say from day 500 to 900, and compare its decline with the $^{56}$Co decay input: the radioactive model predicts the line should follow that radioactive input, while a circumstellar-interaction origin would give a different light curve. In parallel, a three-dimensional explosion model without imposed macroscopic mixing and with $\delta > 0.5$ would yield a deposited oxygen power far below $10^{41}$ erg s$^{-1}$, directly falsifying the mixing assumption.

Watch

Extended reading notes

Core claim

The central claim, stated in Section 5, is that observed [O III] emission lines can originate from deposition of the radioactive energy of $^{56}$Co decay into oxygen matter, given macroscopic mixing between $^{56}$Co and oxygen. In the model, oxygen receives a fraction $M_O/M$ of the total radioactive luminosity, and gamma-ray absorption is kept weak by the mixing condition $\Delta\tau_\gamma = 2.2\delta < 1$ (velocity separation $\delta < 0.5$); a density contrast $\chi$ then boosts the volumetric deposition. With $M_O = 15\,M_\odot$, $T_e \approx 9000$ K, and $\chi \approx 3$, the computed [O III] doublet luminosity, the 4363/5007 ratio, and the [O III]/[O I] ratio agree with observations, and the thermalization fraction matches a detailed numerical deposition calculation. The favored high oxygen mass, together with the scaling $y_3 \propto M_{\mathrm{Ni}}^{3/2} M^{-7/2}$, leads the author to conclude that the radioactive mechanism, not circumstellar interaction, powers the observed [O III] emission.

Load-bearing premise

The model stands on the assumption that $^{56}$Ni and oxygen are macroscopically mixed so that the gamma-ray optical depth between them satisfies $\Delta\tau_\gamma \approx 2.2\delta < 1$ (velocity separation $\delta < 0.5$), and that a density contrast $\chi \approx 2$\u20133 increases deposition; if real ejecta are not mixed this way, the power deposited in oxygen is too small to produce the observed [O III] luminosity.

Editorial extensions

If this is right

If the model is right, the [O III] luminosity of SN 2018ibb is powered by $^{56}$Co decay in oxygen, so no massive circumstellar shell or pulsational pair-instability interaction is needed to explain the lines.
The inferred oxygen mass of 10–15 $M_\odot$ and temperature near 9000 K place the [O III]-emitting zone in a hot inner region distinct from the cooler outer zone that emits [O I].
The scaling $y_3 \propto M_{\mathrm{Ni}}^{3/2} M^{-7/2}$ predicts that pair-instability supernovae with high nickel mass and low ejecta mass show strong [O III]/[O I] ratios, while those with helium shells and lower nickel mass show ratios tens of times smaller.
The agreement between the modeled thermalization fraction and detailed numerical deposition calculations supports the radioactive deposition picture for oxygen masses near 15 $M_\odot$.
The discrepancy with earlier one-dimensional PISN spectral models is attributed to the lack of macroscopic $^{56}$Ni–oxygen mixing in those models, identifying mixing as a necessary ingredient for radioactivity-powered [O III] emission.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

A testable extension the paper does not perform: track the [O III] 5007 luminosity after day 400; the radioactive model predicts it should decline on the $^{56}$Co decay timescale set by the bolometric input, whereas a circumstellar-interaction origin would give a different decline.
The same mixing condition and scaling could be used as a classification tool: a measured [O III]/[O I] ratio combined with an ejecta-mass estimate would constrain the nickel mass and the degree of mixing in other superluminous supernovae.
If three-dimensional PISN explosion simulations resolve macroscopic mixing, they can check the $\delta < 0.5$ requirement directly; the model implies that mixing must be present at that level or the [O III] line would be far fainter.
The two-zone extension suggested by the paper implies that late-time spectra with better spatial or velocity resolution should show [O III] concentrated at lower velocities than [O I].

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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

Short paper, single author, decent physics. The new thing is applying the well-known radioactive heating mechanism to SN 2018ibb with macroscopic mixing, and deriving a scaling relation for [O III] strength among PISNe. The one-zone model fits the observed [O III] luminosity and the 4363/5007 ratio with Te≈9000 K and χ≈3 for 15 M⊙ oxygen, and similar values for 10 and 5 M⊙. The ionization calculation is standard, and the comparison of ηh with the Spencer-Fano number is a nice cross-check. The scaling relation y3 ∝ Mni^{3/2} M^{-7/2} is derived cleanly and is independent of the fitting; it explains naturally why a low-mass, high-56Ni PISN like 2018ibb would show strong [O III] while a more massive He-core PISN would not. That is the most useful part of the paper.

The soft spots are real but the paper is honest about them. The central reproduction of the [O III] luminosity is a fit to Te and χ; those are the two free parameters, so the agreement in Figure 1 is not a prediction. The model fails on the [O I] 5577 line (predicts it too strong at +276 d) and on the broader [O I] profile; the author says a two-zone model with a cool outer oxygen region is needed, which is a reasonable way out but not demonstrated here. The stress-test note about the energy partition Ld(O)=(MO/M)L also has merit: in a clumpy geometry with χ>1, the gamma-ray absorption in oxygen is not guaranteed to be mass-weighted, and the paper does not compute the covering factor. I would not call it fatal—the clump optical depths are order unity and χ is adjustable—but it adds another layer of freedom to the 'agreement'.

The scaling relation and the explicit call for macroscopic mixing are worth having in the literature. The paper is clearly written, the equations check out, and the author flags the limitations instead of hiding them. A serious referee can engage with whether the two-zone model would actually produce the observed line profiles. I would send it to review. For a reading group, it is a quick, discussable paper on a topical object.

Referee Report

3 major / 6 minor

Summary. SN 2018ibb is a candidate pair-instability supernova whose nebular spectrum shows strong [O III] 5007, 4959, and 4363 Å emission of debated origin. The paper proposes a one-zone radioactive-deposition model: the ejecta are a homogeneous-on-average sphere of 60 Msun and 1.2e52 erg, with 30 Msun of 56Ni macroscopically mixed into oxygen, and the deposited gamma-ray power in oxygen is assumed to be Ld(O) = (MO/M)L. Oxygen ionization is solved in steady state with free electron temperature Te and density contrast chi. The model reproduces the observed [O III] luminosity and line ratios for MO = 15 Msun with Te about 9000 K and chi about 3, and similar solutions for MO = 10 and 5 Msun. Section 4 derives a scaling y3 proportional to Mni^{3/2} M^{-7/2} to explain the range of [O III]/[O I] ratios among PISNe. The paper explicitly acknowledges that the one-zone model cannot reproduce the [O I] 5577 Å nondetection or the broader [O I] profile.

Significance. If the central claim is correct, the strong [O III] emission of SN 2018ibb would be powered by 56Co decay rather than by circumstellar interaction, and the simple scaling relation would provide a testable explanation for why only a few PISNe show strong [O III]. The model is transparent, the parameter set is small, and the scaling relation is a falsifiable prediction. The manuscript also honestly lists its limitations. However, the quantitative support for the mechanism rests on an assumed energy partition and on Te and chi being fitted to the observations, so the evidence presented is weaker than the concluding claim of confirmation.

major comments (3)

[Section 2] The relation Ld(O) = (MO/M)L assumes that oxygen absorbs a mass-weighted share of the total bolometric luminosity, but this is not derived from the clumpy geometry introduced in the same section. With the oxygen filling factor f = (MO/M)chi^{-1} and chi = 3, the covering fraction of optically thick oxygen clumps as seen from 56Co clumps is about f, so the absorbed fraction can be a factor of about chi lower than MO/M. The paper neither computes the coupling between chi and this covering factor nor supplies the clump-size and optical-depth argument needed to justify the mass-weighted partition. Because the [O III] luminosity normalization is the central test of the radioactive mechanism, this missing step is load-bearing.
[Section 3, Figure 1, Table 1] The agreement with the observed [O III] luminosity and the 4363/5007 ratio is achieved by choosing Te and chi; for each assumed MO the parameters are adjusted to pass through the observed point, so the agreement is a two-parameter fit rather than an independent confirmation. The comparison eta_h approximately eta_h,num in Table 1 is a useful internal consistency check, but it uses the same Ld(O) and the same one-zone ionization balance, so it does not by itself establish the radioactive origin of the emission.
[Sections 3 and 4] The acknowledged failures on [O I] 5577 Å and the [O I] line profile are not merely cosmetic. The model predicts a strong 5577 Å line at +276 d that is not observed, and the observed [O I] doublet is broader than [O III], implying different emission zones. The paper defers these issues to a two-zone model; until that model is specified, the reproduced [O III]/[O I] ratio in Figure 1b cannot be regarded as a physical prediction for a single oxygen component, and the concluding sentence in Section 5 is stronger than the demonstrated result.

minor comments (6)

[Introduction and Section 3] The wavelength of the [O III] auroral line is given as 4363 Å in the Introduction but as 4359 Å in Figure 1 and Section 3; one consistent value should be used.
[Throughout] There are numerous typographical errors, e.g., 'deposion', 'fsctor', 'ioniztion', 'distibution', and 'radiactive'; the manuscript needs a careful proofreading pass.
[Section 2] The filling factor f = (MO/M)chi^{-1} is introduced but then plays no explicit role in the deposition or line-luminosity equations; stating where f enters would make the cost of a high density contrast visible.
[Section 2] The extension of w = 2.3I to O II and O III is stated in one sentence; a brief justification or a reference for the ion case would help the reader assess the ionization balance.
[Section 4] The scaling Mni proportional to E^3 is taken from helium-core PISN models, whereas SN 2018ibb is modeled as an oxygen-core explosion; the paper should state whether the same proportionality is expected for oxygen-core ejecta.
[Figure 1 caption] The caption says 'Colored lines show the dependence on the chi parameter for the fixed temperature' and identifies red as 7000 K and green as 10000 K, but the black lines showing the temperature dependence at fixed chi should also be described explicitly in the caption, as they are in the text.

Circularity Check

0 steps flagged · score 1.0 of 10

No significant circularity: the model's free parameters are openly fitted to the [O III] data, and the independent scaling relation is derived from ionization balance and an external M_Ni-E relation.

full rationale

The paper's central claim is explicitly conditional on macroscopic mixing and uses two free parameters, Te and χ. The text labels these as 'the minimum set of free parameters' and says the observed values are 'reproduced' rather than predicted; the agreement is therefore a postdiction, not a hidden prediction. The deposition power Ld(O)=(MO/M)L is an assumed energy partition that could be physically wrong, but it is not the same as setting the [O III] luminosity equal to the input: the line luminosity is obtained by solving ionization-balance and level-population equations with standard atomic data, so the match is not an identity. The scaling relation y3∝Mni^{3/2}M^{-7/2} follows from Eq. (1) together with V∝E^{3/2}/M^{3/2} and the external Kasen et al. (2011) Mni∝E^3 relation, independent of the fitted Te and χ. The self-citation to Chugai (2024) supplies the mod60 reference parameters and the oxygen-core premise, but the [O III] calculation does not reduce to that citation. The acknowledged one-zone limitations are model deficiencies, not circular definitions. Hence no step in the derivation is equivalent to its input by construction.

Assumptions & free parameters 3 free parameters · 6 assumptions · 0 invented entities

Two continuous parameters (Te and chi) and one discrete parameter (MO) are adjusted to match the observed [O III] luminosity and line ratios, so the central reproduction is a fit rather than a prediction. The scaling relation of Section 4 is derived independently from ionization balance and the cited Mni versus E relation. No new physical entities are introduced.

free parameters (3)

electron temperature Te = ~9000 K for MO=15 and MO=10; ~9200 K for MO=5
Adjusted to match the observed [O III] 4363/5007 flux ratio (Figure 1a and text in Section 3).
oxygen density contrast chi = ~3 (MO=15), ~2 (MO=10), ~1 (MO=5)
Adjusted to match the observed [O III] 5007,4959 luminosity; represents the ratio of oxygen density to average ejecta density.
oxygen mass MO = 15, 10, 5 solar masses (chosen, not fitted)
Varied across three values; the 10-15 solar mass cases are preferred based on consistency between the thermal balance efficiency eta_h and the Spencer-Fano estimate eta_h,num.

assumptions (6)

domain assumption Homogeneous one-zone ejecta with free expansion kinematics v = r/t
Section 2 models the envelope as a uniform sphere; the paper calls this an idealization and notes the real density distribution is three-dimensional.
domain assumption Macroscopic mixing of 56Ni and oxygen such that gamma-ray optical depth satisfies Delta tau_gamma = 2.2 delta < 1
Section 2 imposes delta < 0.5 so that cobalt-56 gamma rays reach the oxygen; this is the key assumption that allows radioactive power to drive the oxygen emission.
domain assumption Steady-state ionization balance
Section 2 argues that the recombination time is much shorter than the cobalt decay time and the expansion time, so steady state is a valid approximation.
ad hoc to paper Relation wk = 2.3 Ik for ionization work of O II and O III
Extends the neutral-oxygen relation from Ahlen (1980) to ions without direct experimental calibration; affects the ionization rates used throughout.
domain assumption Neglect of UV resonance line ionization of O I by O II lines
Section 2 states this neglect underestimates the oxygen ionization degree, making the model conservative for the claimed mechanism.
domain assumption Kasen et al. (2011) scaling Mni proportional to E^3 for PISN models
Used in Section 4 to derive y3 proportional to Mni^{3/2} M^{-7/2}; imported from cited prior work and not derived in this paper.

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Cite this review

Pith. "Pith review of PISN 2018ibb: radioactive emission of [O III] lines." pith.science (2026). https://pith.science/paper/45DLIMMM

@misc{pith2026250107134,
  author       = {Pith},
  title        = {Pith review of: PISN 2018ibb: radioactive emission of [O III] lines},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/45DLIMMM}},
  note         = {Machine review of arXiv:2501.07134}
}

abstract

Supernova 2018ibb of the PISN category related to the dynamical instability of oxygen core in a supermassive star induced by pair-creation shows at the nebular stage strong [\oiii] emission lines of an uncertain origin. I propose a simple model that demonstrates a possibility of [O III] lines emission from the supernova oxygen matter ionized and heated by the $^{56}$Co radioactive decay. The reason is pinpointed by which the [O III] line luminosity among supernovae of PISN category can vary in a broad range.

Figures

Figures reproduced from arXiv: 2501.07134 by the authors.

**Figure 1.** Diagnostic diagram "flux ratio vs. [O iii] line luminosity" for the model with 15 M⊙ of oxygen. Left (a) is the diagram for the flux ratio [O iii] 4359˚A/5007,4959˚A; center (b) for the flux ratio [O iii] 5007,4959˚A/[O i] 6300,6364˚A; right (с) for the ratio [O i] 5577˚A/[O i] 6300,6364˚A. Circles show observational values, triangle is for the upper limit of 5577˚A/[O i] 6300,6364˚A flux ratio. Colored lines show… view at source ↗

**Figure 2.** The same as Figure 1, but with the oxygen mass of 5 [PITH_FULL_IMAGE:figures/full_fig_p006_2.png] view at source ↗

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Reference graph

Works this paper leans on

9 extracted references · 9 canonical work pages

[1]

arXiv:2501.07134v1 [astro-ph.HE] 13 Jan 2025 PISN 2018ibb: radioactive emission of [O iii] lines © 2024 N. N. Chugai 1 Institute of Astronomy, Russian Academy of Sciences, Mosco w Submitted 11.11.2024 keywords: stars /emdash.cyr supernovae; stars /emdash.cyr supermassive stars; stars /emdash.cyr nucle- osynthesis PACS codes: 1email: nchugai@inasan.ru 1 Ab...

work page Pith review arXiv 2025
[6]

The power deposited in the oxy gen matter by gamma-quanta of 56Co decay is Ld(O) = ( MO/M)L

that is reproduced in the model mod60 (Chugai 2024). The power deposited in the oxy gen matter by gamma-quanta of 56Co decay is Ld(O) = ( MO/M)L. The deposiion in the unit of volume of the oxygen matter is, therefore, ǫd = Ld(O)/VO) = (L/V )χ = 3.6 × 10−7χ [ erg cm−3 s−1]. The ionization rate of the oxygen k-ion with the ionization potential Ik due to ion...

work page 2024
[7]

The auroral-to-nebular ratio [O i] 5577 ˚ A/6300,6364˚ A (Figure 1,c) is an indicator of the tmperature and electron number density in t he [O i] emission zone

indicating a diﬀerent radia l distribution of sources for these emissions, which is not described by our one-zone model. The auroral-to-nebular ratio [O i] 5577 ˚ A/6300,6364˚ A (Figure 1,c) is an indicator of the tmperature and electron number density in t he [O i] emission zone. Unfortunately, at the stage +276 days the 5577 ˚ A is not seen because it f...

work page 2024
[8]

hot" oxygen with the temperature o f 9000 K emits [O iii] lines, whereas external

It shows, in order, the oxygen mass, temperature, density contrast, i onization degree, power deposition ro oxygen material, total luminosity of ox ygen lines, deposi- tion fraction estimated from the energy thermal balnce ηh = Lem(O)/Ld(O), and ﬁnally, the theoretical estimate using derived ionizat ion degree and the relation ηh,num (xe) for the oxygen f...

work page 1992
[24]

2002, Barkat et al

is the very likely case of pair-instability supernovae (PISN) (Wo osley et al. 2002, Barkat et al

work page 2002
[1967]

The light curve in the range of about 1000 d ays indicates that SN 2018ibb is caused by the supermassive star explosion with the energy of /greaterorsimilar1052 erg and the ejection of enormous amount (25–44 M⊙) of synthesised 56N (Schulze et al. 2024). Large values of energy and 56Ni mass suggest the presupernova initial mass of 140–260 M⊙ and the explos...

work page 2024
[2002]

2024, Kozyreva et al

does not show noticeable [O iii] 5007 ˚ A emission (Schulze et al. 2024, Kozyreva et al. 2024). Given uncertainty of the [O iii] emission origin, it is premature to abandon the radiactive mechanism, because it might well be that the r eal supernova envelope of SN 2018ibb diﬀers signiﬁcantly from the theoret ical model based on the one-dimensional explosio...

work page 2024
[2017]

Superluminous supernova SN 2018ibb: Circumstellar shell and spectral effects

is not able to rep roduce the [O iii] luminosity of SN 2018ibb despite being based on the hydrody namic PISN model. A possible reason is that the one-dimensional PI SN model does not produce the signiﬁcant macroscopic mixing of the 56Ni in the unburned oxygen. Meanwhile such a mixing is a crucial ingredient that signiﬁcantly increases the gamma-quanta dep...

work page Pith review arXiv 1980

Show all 9 references

[2024]

It should be emphasised that this model is also an approximat ion based on the Arnett (1980) description

with the ejecta mass of M = 60 M⊙, energy E = 1.2 × 1052 erg, and 56Ni mass Mni = 30 M⊙. It should be emphasised that this model is also an approximat ion based on the Arnett (1980) description. Principal parameters of our mod el are consistent qualitatively with the explosive...

1980

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Reviewed August 10, 2026 · model on record in the stance chip above.

[1] [1]

arXiv:2501.07134v1 [astro-ph.HE] 13 Jan 2025 PISN 2018ibb: radioactive emission of [O iii] lines © 2024 N. N. Chugai 1 Institute of Astronomy, Russian Academy of Sciences, Mosco w Submitted 11.11.2024 keywords: stars /emdash.cyr supernovae; stars /emdash.cyr supermassive stars; stars /emdash.cyr nucle- osynthesis PACS codes: 1email: nchugai@inasan.ru 1 Ab...

work page Pith review arXiv 2025

[2] [6]

The power deposited in the oxy gen matter by gamma-quanta of 56Co decay is Ld(O) = ( MO/M)L

that is reproduced in the model mod60 (Chugai 2024). The power deposited in the oxy gen matter by gamma-quanta of 56Co decay is Ld(O) = ( MO/M)L. The deposiion in the unit of volume of the oxygen matter is, therefore, ǫd = Ld(O)/VO) = (L/V )χ = 3.6 × 10−7χ [ erg cm−3 s−1]. The ionization rate of the oxygen k-ion with the ionization potential Ik due to ion...

work page 2024

[3] [7]

The auroral-to-nebular ratio [O i] 5577 ˚ A/6300,6364˚ A (Figure 1,c) is an indicator of the tmperature and electron number density in t he [O i] emission zone

indicating a diﬀerent radia l distribution of sources for these emissions, which is not described by our one-zone model. The auroral-to-nebular ratio [O i] 5577 ˚ A/6300,6364˚ A (Figure 1,c) is an indicator of the tmperature and electron number density in t he [O i] emission zone. Unfortunately, at the stage +276 days the 5577 ˚ A is not seen because it f...

work page 2024

[4] [8]

hot" oxygen with the temperature o f 9000 K emits [O iii] lines, whereas external

It shows, in order, the oxygen mass, temperature, density contrast, i onization degree, power deposition ro oxygen material, total luminosity of ox ygen lines, deposi- tion fraction estimated from the energy thermal balnce ηh = Lem(O)/Ld(O), and ﬁnally, the theoretical estimate using derived ionizat ion degree and the relation ηh,num (xe) for the oxygen f...

work page 1992

[5] [24]

2002, Barkat et al

is the very likely case of pair-instability supernovae (PISN) (Wo osley et al. 2002, Barkat et al

work page 2002

[6] [1967]

The light curve in the range of about 1000 d ays indicates that SN 2018ibb is caused by the supermassive star explosion with the energy of /greaterorsimilar1052 erg and the ejection of enormous amount (25–44 M⊙) of synthesised 56N (Schulze et al. 2024). Large values of energy and 56Ni mass suggest the presupernova initial mass of 140–260 M⊙ and the explos...

work page 2024

[7] [2002]

2024, Kozyreva et al

does not show noticeable [O iii] 5007 ˚ A emission (Schulze et al. 2024, Kozyreva et al. 2024). Given uncertainty of the [O iii] emission origin, it is premature to abandon the radiactive mechanism, because it might well be that the r eal supernova envelope of SN 2018ibb diﬀers signiﬁcantly from the theoret ical model based on the one-dimensional explosio...

work page 2024

[8] [2017]

Superluminous supernova SN 2018ibb: Circumstellar shell and spectral effects

is not able to rep roduce the [O iii] luminosity of SN 2018ibb despite being based on the hydrody namic PISN model. A possible reason is that the one-dimensional PI SN model does not produce the signiﬁcant macroscopic mixing of the 56Ni in the unburned oxygen. Meanwhile such a mixing is a crucial ingredient that signiﬁcantly increases the gamma-quanta dep...

work page Pith review arXiv 1980