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arxiv: 2511.12362 · v1 · submitted 2025-11-15 · 🌌 astro-ph.HE · astro-ph.SR

Characterization of type Ibn SNe

D. Farias , C. Gall , V. A. Villar , K. Auchettl , K. M. de Soto , A. Gagliano , W. B. Hoogendam , G. Narayan
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A. Sedgewick S. K. Yadavalli Y. Zenati C. R. Angus K. W. Davis J. Hjorth W. V. Jacobson-Gal\'an D. O. Jones C. D. Kilpatrick M. J. Bustamante Rosell D. A. Coulter G. Dimitriadis R. J. Foley A. Gangopadhyay H. Gao M. E. Huber L. Izzo J. L. Johnson A. L. Piro A. Rest C. Rojas-Bravo M. R. Siebert K. Taggart S. Tinyanont
This is my paper

Pith reviewed 2026-05-17 21:54 UTC · model grok-4.3

classification 🌌 astro-ph.HE astro-ph.SR
keywords Type Ibn supernovaecircumstellar materialbinary progenitorslight curve modelinghelium linesejecta masssupernova diversity
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The pith

Type Ibn supernovae come from binary systems, not single massive stars.

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

The paper assembles the largest catalog of 61 Type Ibn supernovae and models the light curves of 24 events with good multi-band coverage. The fits indicate low ejecta masses around one solar mass and modest amounts of helium-rich circumstellar material. These values are too small to match expectations for a single star of roughly ten solar masses exploding at the end of its life. The authors therefore conclude that the progenitors must be binary systems that have lost mass through interaction. This finding matters because it reframes how the narrow helium lines and the surrounding material originate in these explosions.

Core claim

Fitting of the 24 best-observed Type Ibn supernovae with semi-analytical models yields mean ejecta masses of about 1 solar mass expanding at roughly 5000 km/s and circumstellar material masses of about 0.1 solar masses. These masses are inconsistent with single stars of around 10 solar masses at the time of explosion and instead favor binary progenitors.

What carries the argument

Semi-analytical MOSFiT light-curve models that infer ejecta mass, circumstellar material mass, and explosion energy from multi-band photometry.

If this is right

  • The progenitors are binary systems that have undergone mass transfer or common-envelope evolution.
  • The circumstellar material properties align with predictions from binary stellar evolution calculations.
  • Low-energy explosions of stars with compact envelopes surrounded by modest helium-rich shells explain the observed light-curve diversity.
  • Potential companion stars may be detectable in pre-explosion imaging or supernova remnants.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Binary mass transfer offers a natural channel for producing the observed narrow helium lines without requiring extreme mass loss from a single star.
  • Similar mass inferences could be tested on other stripped-envelope supernovae that show interaction signatures.
  • Population synthesis models of binary systems can now be compared directly against the measured ejecta and CSM mass distribution.

Load-bearing premise

The semi-analytical models correctly capture the physics of the light curves and the 24 events with good data represent the broader population without major selection effects.

What would settle it

Direct detection of a single star with mass near 10 solar masses as the progenitor of a future Type Ibn event, or consistent recovery of ejecta masses above 5 solar masses in additional well-observed cases.

Figures

Figures reproduced from arXiv: 2511.12362 by A. Gagliano, A. Gangopadhyay, A. L. Piro, A. Rest, A. Sedgewick, C. D. Kilpatrick, C. Gall, C. R. Angus, C. Rojas-Bravo, D. A. Coulter, D. Farias, D. O. Jones, G. Dimitriadis, G. Narayan, H. Gao, J. Hjorth, J. L. Johnson, K. Auchettl, K. M. de Soto, K. Taggart, K. W. Davis, L. Izzo, M. E. Huber, M. J. Bustamante Rosell, M. R. Siebert, R. J. Foley, S. K. Yadavalli, S. Tinyanont, V. A. Villar, W. B. Hoogendam, W. V. Jacobson-Gal\'an, Y. Zenati.

Figure 1
Figure 1. Figure 1: Visualization of the four different SN Ibn samples (F25, X￾RAY, MOSFiT, and Literature) analyzed in this work, with the individual member SN labeled. For details, see Tables B.6 and B.6). lower-mass stars, such as an accreting helium star (M∗ ≲ 5 M⊙) and a compact object (e.g., a neutron star) have also been pro￾posed for SNe Ibn 2006jc and 2019uo (Tsuna et al. 2024a). A similar scenario invoking an unstab… view at source ↗
Figure 2
Figure 2. Figure 2: Interpolated B−V (upper panel) and g−r (lower panel) curves for the 24 SNe Ibn from F25 (magenta filled circles), the Icn/Ibn (2023emq￾like; yellow filled circles) and the color curves (±1σ) of the Literature (Lit.) sample (blue regions). The color curves (±1σ) of five SNe Icn are included for comparison (red regions). The photometric data of the SNe Icn are retrieved from Gal-Yam et al. (2022); Perley et … view at source ↗
Figure 4
Figure 4. Figure 4: Absolute (R/r-band) peak magnitude versus the absolute value of the slope parameters of the (R/r-band) light curves (γ). The SNe Ibn from the F25 and Literature sample are presented as magenta and blue circles, respectively. Panels upper left, upper right, lower left and lower right show the light curve slopes γ−10 (−10 to tmax), γ+10 (tmax to day +10), γ+20 (+10 to +20 days), and γ+30 (+20 to +30 days), r… view at source ↗
Figure 3
Figure 3. Figure 3: Upper panel: Absolute R/r-band-like light curves of all SNe Ibn from F25 sample that are first reported in this work (magenta dots) and Literature sample (blue lines). Gray (H17) regions correspond to the average light curve and 1.96σ error bars of 18 type Ibn SNe from Hosseinzadeh et al. (2017). Yellow dots correspond to the likely Icn/Ibn SNe 2023emq (Pursiainen et al. 2023), 2023qre, 2023rau and 2023xgo… view at source ↗
Figure 6
Figure 6. Figure 6: Median values ±1σ uncertainties of MOSFiT parameters for all 24 SNe in the MOSFiT sample. The parameters shown here are Mej, vej, ρCSM ×10−12 (labeled in the figure as ρ−12), R0 ×1014 (labeled in the figure as R0,14), s, n and texp for the CSI (circle) and RD+CSI (square) models. The blue circle in each plot highlights the type Ibn OGLE-2014-SN-131. For the CSI sample, the lime and crimson circles correspo… view at source ↗
Figure 7
Figure 7. Figure 7: Left panel: Median values of the posterior distributions of R0 versus ρCSM for each SN in the MOSFiT sample under the CSI model, using prior distributions A (yellow circles) and B (orange squares). Right panel: Same as the left panel, for the RD+CSI case. crepancies in the nickel and the ejecta masses are related to the underlying models used to estimate these parameters. For exam￾ple, Pastorello et al. (2… view at source ↗
Figure 8
Figure 8. Figure 8: Left panel: Mass-loss rates versus the duration of the X-ray event of 15 Ibn SNe of the F25 sample observed with Swift XRT. The mass￾loss rates were estimated using Eq. 1. Right panel: Parameter space of Margalit et al. (2022), ˜vLX/νX versus ˜vtX. Here we included the X￾ray estimates from the type Ibn SN 2006jc (Immler et al. 2008), and the type IIn SNe 2006jd (Chandra et al. 2012) and 2010jl (Chandra et … view at source ↗
Figure 9
Figure 9. Figure 9: Probability density function (PDF) of the narrow (lime) and broad (red) velocity components of He i λ5876 lines of 59 SNe Ibn de￾rived using KDE (solid lines). Lime and red histograms correspond to the empirical velocity measurements used to estimate the PDFs. The black dashed line marks v = 2300 km/s. data from their analysis were published (e.g., P16, Smartt et al. 2016). In these cases, we take the velo… view at source ↗
Figure 10
Figure 10. Figure 10: Upper left: Velocity of the CSM versus the CSM mass retrieved from the CSI modeling of 24 SNe Ibn of the MOSFiT sample. The ve￾locity of the CSM was estimated either from the minimum of the ab￾sorption component of the P-Cygni profile (red circles) or the FWHM of the emission component (olive squares) of He i λ5876 Å line. Upper right: Similar to upper left, velocity of the CSM versus the CSM den￾sity. Bo… view at source ↗
read the original abstract

Type Ibn supernovae (SNe) are characterized by narrow helium (He I) lines from photons produced by the unshocked circumstellar material (CSM). About 80 SNe Ibn have been discovered to date, and only a handful have extensive observational records. Thus, many open questions regarding the progenitor system and the origin of the CSM remain. Here we investigate potential correlations between the spectral features of the prominent He I $\lambda$5876 line and the optical and X-ray light curve properties of SNe Ibn. We compile the largest sample of 61 SNe Ibn to date, of which 24 SNe have photometric and spectroscopic data from the Young Supernova Experiment and 37 SNe have archival data sets. We fit 24 SNe Ibn with sufficient photometric coverage ($B$ to $z$ bands) using semi-analytical models from MOSFiT. We demonstrate that the light curves of SNe Ibn are more diverse than previous analyses suggest, with absolute $r$-band peak magnitudes of $-19.4\pm0.6$~mag and rise (from $-10$ days to peak) and decay-rates (from peak to +10 days) of $-0.08\pm0.06$ and $0.08\pm0.03$ mag/day, respectively. We find that the majority of SNe Ibn in the sub-sample are consistent with a low-energy explosion ($<10^{51}$ erg) of a star with a compact envelope surrounded by $\sim$0.1 M$_{\odot}$ of helium-rich CSM. The inferred ejecta masses are small ($\sim 1$ M$_{\odot}$) and expand with a velocity of $\sim$5000 km/s. Our spectroscopic analysis shows that the mean velocity of the narrow component of the He I lines, associated to the CSM, peaks at $\sim1100$ km/s. The mean CSM and ejecta masses inferred for a sub-sample of SNe Ibn indicate that their progenitors are not massive ($\sim10$ M$_{\odot}$), single stars at the moment of explosion, but are likely binary systems. This agrees with the detection of potential companion stars of SNe Ibn progenitors, and the inferred CSM properties from stellar evolution models.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript compiles the largest sample to date of 61 Type Ibn supernovae, of which 24 have sufficient multi-band photometry to be modeled with the semi-analytical MOSFiT code. The fits yield typical ejecta masses of ~1 M⊙, CSM masses of ~0.1 M⊙, low explosion energies (<10^51 erg), and CSM velocities of ~1100 km/s from He I line analysis. These parameters are used to argue that the progenitors are likely binary systems rather than single massive (~10 M⊙) stars at explosion.

Significance. If the mass inferences are robust, the work provides valuable quantitative constraints on SNe Ibn progenitors from a substantial sample, supporting binary channels in agreement with companion detections and stellar evolution models. The compilation of 61 events and consistent fitting of 24 light curves are clear strengths that advance the field.

major comments (2)
  1. [Light-curve modeling and results] The central claim that progenitors are binary systems (abstract and conclusion) rests directly on the mean ejecta (~1 M⊙) and CSM (~0.1 M⊙) masses from MOSFiT fits to the 24-event subsample. The semi-analytical models adopt a power-law CSM density profile, constant opacity, and spherical symmetry without cross-checks against radiation-hydrodynamics calculations or alternative prescriptions for helium-rich CSM; any deviation can shift recovered masses by factors of several while still matching the photometry.
  2. [Abstract and results section] The abstract and results report mean mass and velocity values but provide no per-event error bars, reduced chi-squared statistics, or other goodness-of-fit metrics for the 24 MOSFiT fits. This omission makes it difficult to assess how well the models represent the data and the robustness of the means that exclude single-star progenitors.
minor comments (2)
  1. [Sample description] The selection criteria used to identify the 24 events with sufficient photometric coverage from the full set of 61 should be stated more explicitly to allow evaluation of possible selection biases.
  2. [Figures] Light-curve figures would benefit from overlaid best-fit MOSFiT models to permit direct visual assessment of fit quality.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their constructive and detailed comments. We address each major comment below and have revised the manuscript to improve clarity and robustness where appropriate.

read point-by-point responses

  1. Referee: [Light-curve modeling and results] The central claim that progenitors are binary systems (abstract and conclusion) rests directly on the mean ejecta (~1 M⊙) and CSM (~0.1 M⊙) masses from MOSFiT fits to the 24-event subsample. The semi-analytical models adopt a power-law CSM density profile, constant opacity, and spherical symmetry without cross-checks against radiation-hydrodynamics calculations or alternative prescriptions for helium-rich CSM; any deviation can shift recovered masses by factors of several while still matching the photometry.

    Authors: We acknowledge that the semi-analytical MOSFiT models rely on simplifying assumptions including a power-law CSM density profile, constant opacity, and spherical symmetry. These choices follow standard practice for fitting large samples of interacting supernovae and are consistent with prior validations in the literature. While dedicated radiation-hydrodynamics calculations for the full sample lie beyond the scope of this observational study, the inferred parameters align with independent spectroscopic velocity measurements of the narrow He I components. To address the concern, we will expand the discussion section to explicitly quantify potential systematic uncertainties in the mass recovery and note that even allowing for factor-of-several variations, the typical ejecta masses remain far below those expected for single ~10 M⊙ stars at explosion. We have made a partial revision by adding this discussion. revision: partial

  2. Referee: [Abstract and results section] The abstract and results report mean mass and velocity values but provide no per-event error bars, reduced chi-squared statistics, or other goodness-of-fit metrics for the 24 MOSFiT fits. This omission makes it difficult to assess how well the models represent the data and the robustness of the means that exclude single-star progenitors.

    Authors: We agree that reporting per-event uncertainties and goodness-of-fit metrics will strengthen the presentation and allow better evaluation of the fits. In the revised manuscript we will include a table in the results section listing the best-fit ejecta mass, CSM mass, explosion energy, and reduced chi-squared (or equivalent MOSFiT statistic) for each of the 24 events, together with the associated uncertainties. revision: yes

Circularity Check

0 steps flagged

No circularity: masses inferred from external MOSFiT fits to photometry, then interpreted against single-star expectations

full rationale

The paper compiles 61 SNe Ibn, fits 24 with sufficient photometry using the external semi-analytical MOSFiT code, reports mean ejecta mass ~1 M⊙ and CSM mass ~0.1 M⊙, and concludes these values imply binary rather than single ~10 M⊙ progenitors. This chain does not reduce any claimed prediction or uniqueness result to a fitted parameter by construction, nor does it rely on self-citation load-bearing steps, ansatz smuggling, or renaming. The model assumptions (power-law CSM, constant opacity, spherical symmetry) are external to the paper and the conclusion is an interpretive comparison rather than a tautological output. The derivation remains self-contained against the input photometry and the cited external code.

Axiom & Free-Parameter Ledger

3 free parameters · 2 axioms · 0 invented entities

Central claims rest on semi-analytical light-curve modeling whose free parameters are fitted to data and on standard assumptions about spherical symmetry and radiative transfer in supernova atmospheres.

free parameters (3)
  • ejecta mass
    Fitted parameter in MOSFiT models for the 24 events; reported mean ~1 solar mass.
  • CSM mass
    Fitted parameter; reported mean ~0.1 solar mass of helium-rich material.
  • explosion energy
    Fitted; constrained to <10^51 erg for the majority of the sub-sample.
axioms (2)
  • domain assumption MOSFiT semi-analytical models correctly describe the interaction between ejecta and helium-rich CSM.
    Invoked when fitting the 24 light curves to infer physical parameters.
  • domain assumption The 24 events with sufficient photometric coverage are representative of the full 61-event sample.
    Used to generalize the low-energy, binary-progenitor conclusion.

pith-pipeline@v0.9.0 · 5899 in / 1455 out tokens · 34253 ms · 2026-05-17T21:54:35.662339+00:00 · methodology

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Works this paper leans on

2 extracted references · 2 canonical work pages

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    (2012), [9] Hosseinzadeh et al

    Smith et al. (2012), [9] Hosseinzadeh et al. (2017), [10] Sanders et al. (2013), [11] Pastorello et al. (2015b), [12] Pastorello et al. (2015e), [13] Gorbikov et al. (2014), [14] Pastorello et al. (2016), [15] Vallely et al. (2018), [16] Wang et al. (2021), [17] Karamehmetoglu et al. (2017), [18] Pastorello et al. (2015c), [19] Shivvers et al. (2017), [20...

    work page 2012

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    (2024), [37] Pursiainen et al

    Pellegrino et al. (2024), [37] Pursiainen et al. (2023), [38] This work. (□) Abbreviations for OGLE-2012-SN-006 (OGLE-12), ASASSN-14ms (14ms), OGLE-2014-SN-131 (OGLE-14) and ASASSN-15ed (15ed). (⋆) The peak time and corresponding magnitude of SN 2022qhy and SN 2023abbd correspond to the first observation inVandobands of those SNe, respectively. (†††) SN 2...

    work page 2024