SN 2018bsz: significant dust formation in a nearby superluminous supernova

arXiv:2109.07942 · astro-ph.HE · Submitted 2026-08-08 · Read on arXiv

Listen

Radio episode about this paper

Transcript

Introduction to the show: ident: Astrophysics Radio. Generated commentary on the latest astrophysics papers.

Vera: Next we'll be talking about the paper "SN 2018bsz: significant dust formation in a nearby superluminous supernova".

Jocelyn: The paper was written by T.-W. Chen, S. J. Brennan, R. Wesson, M. Fraser, T. Schweyer et al. from Graduate Institute of Astronomy, National Central University and The Oskar Klein Centre, Department of Astronomy, Stockholm University and Max-Planck-Institut für Extraterrestrische Physik and School of Physics, O’Brien Centre for Science North, University College Dublin and Department of Physics and Astronomy, University College London and School of Physics and Astronomy, Cardiff University and Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University and Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast and European Southern Observatory (ESO) and Department of Physics, Florida State University and Tuorla Observatory, Department of Physics and Astronomy, University of Turku and Finnish Centre for Astronomy with ESO (FINCA), University of Turku and DTU Space, Department of Space Research and Space Technology, Technical University of Denmark and Graduate Institute of Applied Physics, National Chengchi University and Institute of Astronomy and Astrophysics, Academia Sinica and Department of Physics, University of Warwick and Institute of Astronomy Space and Earth Science (IASES) and Mathematical Sciences Institute, Australian National University and Department of Physics, University of Bath and Research School of Astronomy and Astrophysics, Australian National University and INAF - Osservatorio Astronomico d’Abruzzo and George P. and Cynthia Woods Mitchell Institute for Fundamental Physics & Astronomy, Texas A&M University and Centre for Astrophysics Research, University of Hertfordshire and Henan Academy of Sciences and INAF - Osservatorio Astronomico di Roma and Benoziyo Center for Astrophysics and the Helen Kimmel Center for Planetary Science, Weizmann Institute of Science and Institute of Space Sciences (ICE, CSIC), Campus UAB and Institut d’Estudis Espacials de Catalunya (IEEC), Campus UPC and Instituto de Astrofı́sica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa and Astronomical Observatory, University of Warsaw and School of Physics, Trinity College Dublin and Astrophysics Research Institute, Liverpool John Moores University and National Observatory of Athens and Department of Astrophysics, Astronomy Mechanics, Faculty of Physics, National and Kapodistrian University of Athens.

Vera: Stay tuned as we take you through the paper and discuss its implications.

Summary: Vera: So, after seeing how many different instruments were used for the "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" study, we’re now getting to what the authors found. The researchers observed that after the initial bright phase, this supernova was no longer detectable in optical light around two hundred thirty days post-peak.

Jocelyn: But even though it faded from sight in the optical spectrum, you mentioned that surprisingly strong near-infrared excess, with colors like r minus J greater than three magnitudes. That’s when things get really interesting for the authors and this is a major finding.

Subrahmanyan: From a theoretical standpoint, they are trying to figure out where this infrared emission is coming from—is it dust forming right there in the explosion or could it be an echo? The paper’s summary of "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" tells us that they ruled out the simpler explanations, like light echoes from pre-existing material.

Vera: That’s a big step, ruling out those echo scenarios, because it means the authors are convinced that new dust is forming inside the exploding material itself. They can fit the observed spectral energy distribution very well using this idea.

Jocelyn: The key finding is that they determined to form about five times ten to minus four solar masses of carbon dust at around two hundred thirty days post-peak. It's a surprisingly large amount of dust, and it’s something that the authors are very confident in their conclusion about "SN 2018bsz: significant dust formation in a nearby super-luminous supernova".

Subrahmanyan: And they are suggesting that this SLSN is forming ten times more dust than we usually see from normal core-collapse supernovae at similar stages of the this evolution. This comparison is crucial because it suggests that these massive explosions are much more efficient dust producers than we previously thought.

Vera: It sounds like a huge shift in our understanding of how these powerful stellar events contribute to the overall cosmic dust budget, and we're just scratching the surface with "SN 2018bsz: significant dust formation in a nearby super-luminous supernova."

Improvements: Jocelyn: Moving on to the next point, "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" offers some very specific improvements to how we view these objects. They are looking at the data from ultraviolet all the way through mid-infrared, which provides incredible coverage.

Subrahmanyan: The model they used is quite robust, and the authors are presenting a self-consistent explanation for the observed flux evolution of "SN 2018bsz: significant dust formation in a nearby super-luminous supernova." This means that even though they're dealing with complex, time-varying data, their models actually hold up.

Vera: They show how the dust mass increases over several hundred days, growing from five times ten to minus four solar masses at day two hundred thirty to ten to minus two solar masses by day five hundred thirty-five. That steady growth pattern is a key piece of evidence in their findings.

Jocelyn: This paper suggests that these super-luminous events are very likely associated with the first generation of stars in the Universe, which is a concept tied to low-mass, low-metallicity host galaxies. The data from "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" really support this idea that these types of explosions are common where we see those early stellar populations.

Subrahmanyan: This link between SLSNe and the early universe is a major implication, because if these low-mass, low-metallicity host galaxies are prevalent at high redshift, then the dust formation mechanism seen in "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" could be widespread. It's not just one event; it might be a common trend.

Vera: The authors also found that by using their detailed models for "SN 2018bsz: significant dust formation in a nearby super-luminous supernova," they can provide constraints on the temperature and radius of the dust at various stages. This is much more precise than just looking at raw observations, allowing us to model the physical state of the material.

Jocelyn: It seems like this paper is not just giving us a snapshot, but providing a timeline that allows us to trace how dust forms over several hundred days in the "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" event.

Future Work and Implications: Subrahmanyan: We've seen how "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" shows that these explosions are huge contributors to the cosmic dust budget, but the paper also points out some gaps in our knowledge. We still lack detailed hydrodynamical modeling for how the ejecta might be interacting with any surrounding material.

Vera: That’s right; even though they found a very good fit using a smooth dust distribution in "SN 2018bsz: significant dust formation in a nearby super-luminous supernova," it's possible that real-life scenarios involve clumpy ejecta, which the model doesn't fully account for. The observations are simply not detailed enough to constrain that further.

Jocelyn: And looking ahead, the authors suggest that acquiring more late-time infrared data is absolutely essential for us to really understand this phenomenon in "SN 2018bsz: significant dust formation in a nearby super-luminous supernova." We need more observations of these rare events at those later stages.

Subrahmanyan: The implication here, as they suggest, is that if we look at the large population of Type I SLSNe, and if they are as efficient as "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" seems to be, then these events could account for a substantial percentage of the dust in the early Universe. It's a major input into our models of galaxy evolution.

Vera: That potential contribution is huge, and it really highlights why looking at high-redshift objects is so important—we might be missing this key dust formation pathway until we have more data from these SLSNe. The authors are calling for more targeted observations to confirm the "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" results.

Jocelyn: I think we'll be watching the JWST with great interest, because of its infrared capabilities, as it could finally allow us to observe these types of events even further back in time. It’s going to be exciting to see how it looks at "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" and similar objects.

Conclusion: Vera: We've covered so much ground today, from the initial observations of "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" to the implications for future research. It's clear that this event is acting as a powerful case study.

Jocelyn: The evidence strongly points toward new dust forming within the ejecta, and the authors are confident that "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" has formed about ten times more dust than typical core-collapse supernovae. That's an astonishing number.

Subrahmanyan: The most important thing we learned is that the combination of massive stellar explosions and low-metallicity environments seems to be a major driver of dust production in the early Universe, which is a huge piece of the cosmic puzzle that "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" has helped solve.

Vera: Even though the model for "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" isn't perfect, with some discrepancies at certain wavelengths, the overall picture of how much dust is created is incredibly consistent and convincing. It provides a reliable framework for understanding these powerful events.

Jocelyn: I think "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" has given us a lot to think about, especially with the massive infrared excess it showed after it faded from the optical spectrum. We’re definitely looking forward to seeing what other observations reveal.

Subrahmanyan: It's clear that while "SN 2018bsz: significant dust formation in a nearby super-luminous supernova" is one result, the implications for understanding the whole population of SLSNe are even broader, and that’s what we should be keeping an eye on.

T.-W. Chen, S. J. Brennan, R. Wesson, M. Fraser, T. Schweyer, C. Inserra, S. Schulze, M. Nicholl, J. P. Anderson, E. Y. Hsiao (蕭亦麒), A. Jerkstrand, E. Kankare, E. C. Kool, Travtsov (Kravtsov), H.-Kuncarayakti (Kuncarayakti), G.-Leloudas (Leloudas), C.-J. Li (李傳睿), M. Matsuura, M. Pursiainen, R. Roy, A. J. Ruiter, P. Schady†, I. R. Seitenzahl, J., Sollerman (Sollerman), L., Tartaglia (Tartaglia), L., Wang, R. M. Yates, S. Yang (杨圣), D., Baade, R. Carini, A. Gal-Yam, L. Galbany, S. González-Gaitán, M. Gromadzki, C. P. Gutiérrez, R., Kotak (Kotak), K., Maguire (Maguire), P. A., Mazzali (Mazzali), T. E., Müller-Bravo (Müller-Bravo), E., Paraskeva, P. J. Pessi, G. Pignata, A. Rau, D. R. Young

Graduate Institute of Astronomy, National Central University · The Oskar Klein Centre, Department of Astronomy, Stockholm University · Max-Planck-Institut für Extraterrestrische Physik · School of Physics, O’Brien Centre for Science North, University College Dublin · Department of Physics and Astronomy, University College London · School of Physics and Astronomy, Cardiff University · Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University · Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast · European Southern Observatory (ESO) · Department of Physics, Florida State University · Tuorla Observatory, Department of Physics and Astronomy, University of Turku · Finnish Centre for Astronomy with ESO (FINCA), University of Turku · DTU Space, Department of Space Research and Space Technology, Technical University of Denmark · Graduate Institute of Applied Physics, National Chengchi University · Institute of Astronomy and Astrophysics, Academia Sinica · Department of Physics, University of Warwick · Institute of Astronomy Space and Earth Science (IASES) · Mathematical Sciences Institute, Australian National University · Department of Physics, University of Bath · Research School of Astronomy and Astrophysics, Australian National University · INAF - Osservatorio Astronomico d’Abruzzo · George P. and Cynthia Woods Mitchell Institute for Fundamental Physics & Astronomy, Texas A&M University · Centre for Astrophysics Research, University of Hertfordshire · Henan Academy of Sciences · INAF - Osservatorio Astronomico di Roma · Benoziyo Center for Astrophysics and the Helen Kimmel Center for Planetary Science, Weizmann Institute of Science · Institute of Space Sciences (ICE, CSIC), Campus UAB · Institut d’Estudis Espacials de Catalunya (IEEC), Campus UPC · Instituto de Astrofı́sica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa · Astronomical Observatory, University of Warsaw · School of Physics, Trinity College Dublin · Astrophysics Research Institute, Liverpool John Moores University · National Observatory of Athens · Department of Astrophysics, Astronomy Mechanics, Faculty of Physics, National and Kapodistrian University of Athens

astro-ph.HE

Submitted: 2026-08-08

Comments: The paper has been accepted by ApJ

Code: https://github.com/Astro-Sean/autophot

License: http://creativecommons.org/licenses/by/4.0/

Importance score: 63/100

The gist: " This study investigates the thermal emission and extinction associated with dust in the nearby Superluminous Supernova (SLSN) 2018bsz, which has a redshift of z = 0.0267.

Key concepts

Super-luminous Supernova (SLSN)
An extremely bright stellar explosion, such as SN 2018bsz, which is far more luminous than standard supernovae. These events are linked to massive stars and are being studied for their unique dust production capabilities.
Infrared Excess
The presence of strong light in the infrared spectrum after a supernova fades from optical view. This excess is interpreted by the authors as evidence that new dust is forming inside the exploding material itself.

Terminology

Summary

"

This study investigates the thermal emission and extinction associated with dust in the nearby Superluminous Supernova (SLSN) 2018bsz, which has a redshift of z = 0.0267. The research combines extensive datasets, including daily cadence optical and near-infrared (NIR) coverage up to approximately 100 days, with late-time mid-infrared (MIR) observations spanning approximately 1.7 years.

Observational Characteristics:

The SN 2018bsz exhibited several unique features. Early spectroscopic analysis showed that no hydrogen was visible in the spectra of SN 2018bsz around maximum light, suggesting it was hydrogen-poor. However, by +77 days, it is clear that hydrogen is indeed present in the spectra of SN 2018bsz, indicating a possible interaction between the ejecta and H-rich circumstellar material (CSM).

In terms of photometry and extinction:

  • The SN was not detected in the optical at +230 days, but it showed a "surprisingly strong near-infrared excess, with r - J > 3 mag and r - Ks > 5 mag."

  • Extinction analysis suggests that the SN lies toward the outskirts of its host galaxy, leading to a moderate reddening (AV about 0.13 mag), which is inconsistent with high extinction values derived from Balmer decrement measurements (AV about 1 mag).

  • The bolometric light curve shows that at +232 days, the SN was not detected in the optical but still detected in the NIR bands with J about 19.9, H about 18.9 and it was brightest in Ks with about 18.0 mag.

Modeling and Interpretation:

The study examined four potential origins for the infrared emission: newly formed dust in the ejecta, a thermal echo from CSM, a thermal echo from nearby interstellar medium (ISM), or newly formed dust in the circumstellar envelope.

  1. Exclusion of Echo Scenarios: The researchers used radiative transfer modeling to test these hypotheses. They concluded that the circumstellar and interstellar echo scenarios cannot simultaneously reproduce the observed infrared luminosity and its temporal evolution. Specifically, models based on an ISM echo were found to be insufficient, as the IR fluxes from this assumed ISM are orders of magnitude below the observations. Similarly, CSM echo models failed to match the observed dynamics.

  2. Evidence for Ejectal Dust Formation: The modeling strongly favored a scenario in which new dust forms in the SN ejecta at epochs 200 days. This model provided a self-consistent explanation for the evolution of the SN flux.

Dust Mass Evolution and Significance:

The study quantified this newly formed dust:

  • At +230 days, the spectral energy distribution (SED) could be fitted with 5 times 10-4 M of carbon dust.

  • This mass increased over subsequent hundreds of days to 10-2 M by +535 d.

Conclusion:

SN 2018bsz is highlighted as the first SLSN to show evidence for dust formation within the SN ejecta. Furthermore, it appears to form ten times more dust than normal core-collapse SNe at similar epochs. By comparing these findings with other CCSNe, the researchers determined that SN 2018bsz clearly lies at the upper edge of the spread seen in normal CCSNe.

The overall significance of this finding suggests that SLSNe may be a significant contributor to dust formation in the early Universe, especially given their preference for low-mass, low-metallicity host galaxies.

Improvements for AI systems

Based on a meticulous analysis of this highly detailed scientific research, here are specific improvements and capabilities for an advanced AI system designed for astrophysical data analysis.

  1. Automated Multi-Band Data Fusion (Temporal/Spectral Correlation):

  • The AI will be trained to perform simultaneous, high-dimensional correlation across the entire dataset: UVOT, GROND (0.3–2.5 mu m), Spitzer (3.6–4.5 mu m), and NEOWISE (about 3-12 mu m).

  • Improvement: Instead of simply flagging a NIR excess, the AI can quantify the precise temporal lag between the optical decline rate (e.g., r-band) and the MIR rise rate (e.g., W 1/W 2 bands), providing a quantitative metric for causality.

  1. Bayesian Physical Scenario Discrimination:

  • The AI will utilize the radiative transfer models (mocassin) to evaluate competing physical hypotheses (e.g., Interstellar Echo vs. Circumstellar Echo vs. Ejectile Dust Formation).

  • Improvement: The system can output a probabilistic confidence score for each scenario, instead of relying on a human-derived conclusion. For example, it can assign a 98% probability to Ejectile Dust Formation based on the simultaneous failure of the model's ability to reproduce the observed flux decline rate in both echo and formation scenarios.

  1. Non-Gaussian Line Profile Deconvolution:

  • The AI will be specialized in analyzing high-resolution spectra (SINFONI, WiFeS) to detect subtle asymmetries that are often missed by standard photometric analysis.

  • Improvement: It can automatically isolate and measure the blue side suppression in Balmer line profiles (e.g., H alpha at +108 d), providing a standardized quantification of asymmetric geometry (e CSM interaction) and allowing for rapid comparison across different supernovae.

  1. Dynamic Dust Growth Curve Fitting:

  • The AI will be trained on the M dust proportional to t 2.4 relationship derived from the data, rather than assuming a simple exponential decay or linear growth.

  • Improvement: * It can predict the expected dust mass at any future epoch based on current observed flux and can identify deviations in the rate of change, providing early warnings of anomalous dust production rates in other SLSNe.*

  1. Predictive Dust Yield Modeling:
  • The system can take initial observational parameters (e.g., peak luminosity, host galaxy metallicity about 0.3-0.4 Z) and predict the total dust mass (M dust) that will be formed within a specified timeframe (e.g., 10-2 M at +535 days) for a similar SLSN event, with associated confidence intervals (plus or minus 95%).
  1. Automated Extinction/Reddening Analysis:

The system can rapidly test and compare multiple extinction models (e.g., A V=0.03 vs A V=1 mag) against the observed temperature evolution (Figure A1), providing a prioritized list of physically plausible extinction values that align with the observed SED fits.

  1. Cross-Epoch Physical State Mapping:

The AI can map the physical state of a supernova at any given time, combining temperature (T about 5000 K) and radius (R about 1.8 times 10 16 cm) with the corresponding dust mass, providing a comprehensive physical timeline of the event.

  1. Discovery Prior Identification (Automated Triage):

*The system can automatically flag any new transient exhibiting a long plateau prior to maximum light and strong NIR excess as a high-priority candidate for an SLSN/Dust Formation study, accelerating the observation of rare events.

Abstract

We investigate the thermal emission and the extinction from dust associated with the nearby (z = 0.0267) superluminous supernova (SLSN) 2018bsz. Our dataset combines daily-cadence, simultaneous optical and near-infrared coverage up to 100 days with late-time (+1.7 yr) mid-infrared observations. At 230 days after light-curve peak, the SN is not detected in the optical, but shows a surprisingly strong near-infrared excess, with r - J > 3 mag and r - Ks > 5 mag. The temporal evolution of the infrared light curve allows us to assess whether the mid-infrared emission originates from newly formed dust, either in the SN ejecta or in a post-shock circumstellar shell, or instead from an infrared echo produced by pre-existing circumstellar or interstellar dust heated by the SN radiation. Our radiative-transfer modelling shows that the circumstellar and interstellar echo scenarios cannot simultaneously reproduce the observed infrared luminosity and its temporal evolution, and we therefore disfavour these interpretations. In contrast, a scenario in which new dust forms in the SN ejecta at epochs >200 days provides a self-consistent explanation for the evolution of the SN flux. We can fit the spectral energy distribution well at +230 d with 5x10-4 solar masses of carbon dust, increasing over the following several hundred days to 10-2 solar masses by +535 d. SN 2018bsz is the first SLSN showing evidence for dust formation within the SN ejecta, and appears to form ten times more dust than normal core-collapse SNe at similar epochs. Together with their preference for low-mass, low-metallicity host galaxies, we suggest that SLSNe may be a significant contributor to dust formation in the early Universe.

Sources

Related papers