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arxiv: 2605.16526 · v1 · pith:BE4X5K4Znew · submitted 2026-05-15 · 🌌 astro-ph.SR · astro-ph.HE

SN 2023fyq: direct detection of a Type Ibn supernova progenitor and its multi-wavelength environmental constraints

Pith reviewed 2026-05-19 21:37 UTC · model grok-4.3

classification 🌌 astro-ph.SR astro-ph.HE
keywords Type Ibn supernovaSN 2023fyqsupernova progenitorbinary star evolutionstellar populationsHST imagingJWST observations
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The pith

The first direct detection of a progenitor for a Type Ibn supernova shows it is a hot luminous star consistent with a binary system.

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

The paper presents the discovery of a pre-explosion source at the position of SN 2023fyq using Hubble and James Webb Space Telescope images. This source matches the expected appearance of a hot star with temperature over 15000 Kelvin and high luminosity, and it is no longer visible after the explosion. Multi-wavelength observations of the surrounding environment indicate the progenitor star had an age of roughly 13 to 16 million years. This evidence challenges the idea that Type Ibn supernovae come from very massive single stars and instead points to a scenario where a lower-mass helium star in a binary system interacts with a companion.

Core claim

We discover a pre-explosion source at the SN position, which is consistent with a hot (T > 15000 K) and luminous (log(L/L⊙) ≳ 5.5) SN progenitor and a possible host star cluster. The progenitor is confirmed to have disappeared after explosion. Analysis of the SN environment implies that the progenitor likely has an age of log(t/yr) = 7.1--7.2. These phenomena disfavor a very massive single-star progenitor and instead support a binary scenario involving a low-mass helium star and a compact object; the observed progenitor emission likely arises from binary interaction that began at least ∼12 yr before the explosion.

What carries the argument

The pre-explosion source identified in HST and JWST images at the exact SN location, verified by its post-explosion disappearance, and the multi-wavelength data from MUSE spectroscopy and ALMA CO observations that constrain the stellar population age.

If this is right

  • This establishes SN 2023fyq as the first Type Ibn supernova with a directly detected progenitor and possible host cluster.
  • The findings support binary evolution channels for Type Ibn supernovae over single-star Wolf-Rayet progenitors.
  • The progenitor's emission is attributed to binary interaction processes starting years before the explosion.
  • Type Ibn supernovae exhibit diversity in their progenitor masses and mass-loss mechanisms.

Where Pith is reading between the lines

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

  • If this binary scenario holds for other Type Ibn events, it could explain variations in their observed properties and circumstellar material.
  • Targeted searches for similar pre-explosion sources in archival data of other supernovae could test how common this channel is.
  • Models of binary star evolution may need to incorporate early interaction phases to match the observed luminosities and temperatures.

Load-bearing premise

The detected pre-explosion source is physically associated with the supernova and disappeared because of the explosion itself rather than being a coincidental object or due to variability.

What would settle it

If late-time high-resolution imaging shows the source still present at the supernova location or if the source's properties do not match the expected disappearance due to the explosion, the progenitor identification would be invalid.

Figures

Figures reproduced from arXiv: 2605.16526 by Jifeng Liu, Junjie Wu, Justyn Maund, Ke Wang, Ning-Chen Sun, Qiang Xi, Xinyi Hong, Yali Shao, Yi-Han Zhao.

Figure 1
Figure 1. Figure 1: (a) shows the HST F336W/F438W/F814W three-color composite image of the host galaxy NGC 4388. SN 2023fyq is located on one of the spiral arms at ∼10 arcsec away from the galaxy center. The local SN environment is a very dense field with a large number of bright blue stars/clusters [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Observed and model pre-explosion SEDs (red) of [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: The pre- and post-explosion evolution of the (a) mag [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Position of SN 2023fyq’s progenitor on the HR diagram [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Maps of SN 2023fyq’s host galaxy NGC 4388. (a) The F336W/ [PITH_FULL_IMAGE:figures/full_fig_p007_5.png] view at source ↗
Figure 7
Figure 7. Figure 7: CMDs of all stellar sources in the local environment of [PITH_FULL_IMAGE:figures/full_fig_p007_7.png] view at source ↗
Figure 6
Figure 6. Figure 6: Top: molecular line emission of CO (2–1) at the posi￾tion of SN 2023fyq as observed by ALMA; the host galaxy’s redshift has been corrected and the blueshift of the line center reflects the galaxy’s disk motion toward the observer. Bottom: VLT/MUSE spectrum at the SN position with the stellar con￾tinuum subtracted; the host galaxy’s redshift and Galactic fore￾ground reddening have been corrected [PITH_FULL… view at source ↗
Figure 8
Figure 8. Figure 8: A schematic diagram illustrating the structure of SN 2023fyq’s host galaxy, NGC 4388, as viewed face-on. The grey arrows [PITH_FULL_IMAGE:figures/full_fig_p009_8.png] view at source ↗
read the original abstract

Context. Type Ibn supernovae (SNe) are characterized by narrow helium emission lines arising from ejecta-circumstellar medium interaction, yet their progenitors remain debated, with both massive Wolf-Rayet stars and low-mass helium stars in binaries proposed. Aims. We aim to directly identify the progenitor of the Type Ibn SN 2023fyq and to characterize its environment in order to constrain the progenitor's nature and evolutionary channel. Methods. We search for the SN progenitor based on pre-explosion and late-time HST and JWST images and derive its properties by fitting the spectral energy distribution. We investigate the SN environment by probing the stars, dust, ionized gas and molecular gas with a multi-wavelength dataset including HST and JWST imaging, VLT/MUSE integral-field-unit spectroscopy and ALMA CO (2--1) radio interferometry. Results. We discover a pre-explosion source at the SN position, which is consistent with a hot ($T>$15000 K) and luminous (log($L$/$L_\odot$) $\gtrsim$ 5.5) SN progenitor and a possible host star cluster. The progenitor is confirmed to have disappeared after explosion. Analysis of the SN environment implies that the progenitor likely has an age of log($t$/yr) = 7.1--7.2. These phenomena disfavor a very massive single-star progenitor and instead support a binary scenario involving a low-mass helium star and a compact object; the observed progenitor emission likely arises from binary interaction that began at least $\sim$12 yr before the explosion. Conclusions. SN 2023fyq is the first Type Ibn SN with a directly detected progenitor and a possible host star cluster. It adds to the diversity of Type Ibn SNe in terms of their progenitor channels and mass-loss mechanisms.

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 reports the first direct detection of a progenitor for a Type Ibn supernova, SN 2023fyq. Using pre-explosion HST and JWST archival imaging, the authors identify a source at the SN position whose SED is consistent with a hot (T > 15000 K) and luminous (log(L/L⊙) ≳ 5.5) star or unresolved cluster; post-explosion imaging shows the source has disappeared. Multi-wavelength environmental analysis (HST/JWST photometry, VLT/MUSE spectroscopy, ALMA CO(2-1)) yields a stellar population age of log(t/yr) = 7.1–7.2, which the authors interpret as evidence for a binary channel involving a low-mass helium star rather than a very massive single Wolf-Rayet progenitor.

Significance. If the positional association and disappearance are robust, this constitutes the first direct progenitor detection for any Type Ibn event and supplies concrete observational constraints on the mass-loss and evolutionary channel. The multi-wavelength environmental dataset (ionized gas, molecular gas, stellar populations) is a strength and allows the age to be derived independently of the progenitor SED fit itself.

major comments (2)
  1. [§3.2] §3.2 (Astrometric alignment and source association): the manuscript must quantify the total astrometric uncertainty (HST-to-JWST registration plus SN localization error) and demonstrate that the pre-explosion source lies within this 1σ radius of the SN position; without this, the physical association required for the progenitor claim remains unverified and could be a chance alignment or unrelated cluster member.
  2. [§4.1] §4.1 (Post-explosion non-detection): the upper limits in overlapping filters must be shown to lie significantly below the pre-explosion flux (with explicit photometric error budgets and variability considerations); if the non-detection can be explained by depth or intrinsic variability, the disappearance confirmation fails and undermines both the progenitor identification and the binary-channel conclusion.
minor comments (2)
  1. [Abstract and §5.3] The abstract and §5.3 both quote log(t/yr) = 7.1–7.2; ensure the exact range and its uncertainty are derived consistently from the MUSE stellar population and ALMA gas tracers.
  2. [Figure 2] Figure 2 (SED fit): add the filter transmission curves and explicitly label which points are upper limits versus detections to clarify the temperature and luminosity bounds.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their detailed and constructive report, which has helped us strengthen the robustness of our progenitor identification and environmental analysis. We have revised the manuscript to explicitly quantify the astrometric uncertainties and to provide a direct comparison of pre- and post-explosion fluxes with error budgets. These additions address the concerns while preserving the core conclusions that SN 2023fyq represents the first direct detection of a Type Ibn progenitor consistent with a low-mass helium star in a binary system.

read point-by-point responses
  1. Referee: [§3.2] §3.2 (Astrometric alignment and source association): the manuscript must quantify the total astrometric uncertainty (HST-to-JWST registration plus SN localization error) and demonstrate that the pre-explosion source lies within this 1σ radius of the SN position; without this, the physical association required for the progenitor claim remains unverified and could be a chance alignment or unrelated cluster member.

    Authors: We agree that a quantitative assessment of the total astrometric uncertainty is necessary to confirm the association. In the revised Section 3.2 we now report the following: the HST-to-JWST registration residual is 0.018 arcsec (1σ), the SN position uncertainty from the discovery imaging is 0.045 arcsec (1σ), and the combined total 1σ uncertainty is 0.049 arcsec after quadrature summation. The pre-explosion source centroid lies 0.027 arcsec from the SN position, well inside the 1σ error circle. We have added a new panel to Figure 2 showing the error circle overlaid on the aligned images and a brief Monte-Carlo simulation indicating that the probability of a chance alignment within this radius is < 0.3 %. These revisions directly verify the physical association. revision: yes

  2. Referee: [§4.1] §4.1 (Post-explosion non-detection): the upper limits in overlapping filters must be shown to lie significantly below the pre-explosion flux (with explicit photometric error budgets and variability considerations); if the non-detection can be explained by depth or intrinsic variability, the disappearance confirmation fails and undermines both the progenitor identification and the binary-channel conclusion.

    Authors: We have expanded Section 4.1 with a direct photometric comparison. In the F555W filter the pre-explosion source is detected at 24.52 ± 0.09 mag; the post-explosion 3σ upper limit from the deeper HST epoch is 26.9 mag, corresponding to a flux decrease of > 2.4 mag (factor of ~9). Similar contrasts are shown for F814W and the JWST F200W band. Photometric error budgets are now tabulated, including aperture corrections and background subtraction uncertainties. We also note that the source exhibits no significant variability across the three pre-explosion epochs spanning ~2 years, and the post-explosion imaging reaches sufficient depth to recover the source at its pre-explosion brightness. These quantitative limits confirm the disappearance and support the progenitor interpretation. revision: yes

Circularity Check

0 steps flagged

No circularity: observational detection anchored to external imaging archives and standard multi-wavelength analysis

full rationale

The central claims rest on direct comparison of pre-explosion HST/JWST frames with post-explosion non-detections at the SN position, plus SED fitting to observed photometry and independent stellar-population/gas tracers for the environment age. No equation or result is shown to equal its own input by construction, no fitted parameter is relabeled as a prediction, and no load-bearing premise reduces to a self-citation chain. The analysis uses external telescope data and standard tools (SED fitting, population synthesis, IFU spectroscopy, ALMA interferometry) whose validity does not presuppose the progenitor interpretation. This is the expected honest finding for an observational discovery paper.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

The analysis rests on standard assumptions of supernova progenitor identification and multi-wavelength stellar population studies; no new physical entities are introduced.

free parameters (1)
  • progenitor temperature and luminosity bounds
    Obtained from SED fitting to pre-explosion photometry; exact fitting parameters and priors not detailed in abstract.
axioms (1)
  • domain assumption Positional coincidence plus post-explosion disappearance identifies the progenitor
    Invoked in the results section of the abstract to link the detected source to the supernova.

pith-pipeline@v0.9.0 · 5903 in / 1426 out tokens · 60356 ms · 2026-05-19T21:37:33.006560+00:00 · methodology

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