The debate over the explosion mechanism of core-collapse supernovae remains intense: some researchers support the neutrino mechanism, others the jet-feedback mechanism. This work joins the line of studies on Supernova 1987A, where the morphology of the remnant is used as evidence for one mechanism or the other. Neighboring papers in the archive also analyze the morphology of 1987A, its jets, and rings, but this paper takes a different angle: it examines not the explosion itself, but an event that occurred 20,000 years before, and links it to the problem of 'failed supernovae'.
The author builds an analytical model based on observed parameters of the triple-ring system of Supernova 1987A: the expansion velocity of the equatorial ring is 10.3 km/s, its mass is 0.058 solar masses, and the angular sizes of the rings are known. He calculates the optical depth of the rings to light scattering and estimates what fraction of the central star's radiation would reach an observer in the plane of the equatorial ring. To explain the misalignment of the ring axes and the bipolar ejecta, a scenario of 'late directed rotational accretion' is proposed, based on an estimate of the specific angular momentum imparted to the core by the companion's disruption.
A hypothetical observer in the plane of the equatorial ring would see a luminosity of only 5% of the star's original luminosity between 10 and 500 years after the ring ejection. This value is close to observed failed supernova candidates: N6946-BH1 (13–25% of the progenitor's luminosity) and M31-2014-DS1 (about 7%). After a few thousand years, the ring becomes transparent, and the star returns to normal luminosity. The estimated specific angular momentum of the core spun up by the companion is on the order of 5×$10^{15}$ cm²/s, comparable to convective layer fluctuations but insufficient to form a thin accretion disk.
This work differs from neighboring studies by shifting the focus from the explosion morphology to an event that preceded it by 20,000 years and linking it to the problem of 'failed supernovae'. It is the first attempt to interpret the triple-ring system as the cause of a temporary dimming of the star, rather than merely a consequence of binary interaction. The proposed 'late directed rotational accretion' scenario remains speculative but offers a concrete mechanism to explain the axis misalignment.
The topic could develop toward detailed modeling of radiation transfer through the ring system, including dust and inhomogeneities. Numerical simulations of accretion onto a neutron star with moderate core rotation will also be needed to test whether an accretion belt capable of launching jets actually forms. Observational programs searching for intermediate-luminosity transients in the near-infrared could reveal similar events.
The results will affect the interpretation of failed supernova candidates and the statistics of massive star collapses. The late accretion scenario could be tested in future high-angular-resolution observations of supernova remnants.
Perform numerical simulations of the ring ejection hydrodynamics and radiation transfer to refine the light curve for an equatorial observer. Test the late directed rotational accretion scenario in three-dimensional collapse simulations with moderate core rotation.
For supernova astrophysics, the key unresolved problem is the explosion mechanism. This work links the remnant morphology and the dimming event to the jet-feedback mechanism but does not definitively solve the problem. The question remains open as to how often 'failed supernovae' are actually ILOT-like events and how to distinguish them from true collapses to a black hole.
This section is addressed to the author of the paper and their colleagues. Neighbouring works were found by meaning-based search across our archive, not by word overlap. We do not review: we show the field around the work.
What the work does
The study shows that the progenitor of supernova 1987A, which ejected the triple ring system 20,000 years before the explosion, became dim and red for an observer in the plane of the equatorial ring for several hundred years. Light from the central star was scattered by the outer rings, and its apparent luminosity dropped to 5% of its original value. The author also proposes a scenario of 'late directed rotational accretion' to explain the misalignment between the axes of the triple rings and the bipolar structure of the ejecta.
Where its strength is
The strong point is the new interpretation of the triple ring system as the cause of the temporary dimming of the star, linking it to the problem of 'failed supernovae' and providing a concrete mechanism to explain the morphology.
Where it could go next
Worth trying
Why this may matter
This work offers a fresh perspective on the origin of the triple ring system of SN 1987A and connects it to the open problem of 'failed supernovae', which may stimulate the search for similar events in other objects and refine pre-supernova models.
Nearby works in our archive
The archive is sparse around this work: the closest review is only 0.59, against a usual 0.64. It looks like few have drilled nearby.
The equatorial ring of Supernova 1987A is expanding at 10.3 km/s—30 times slower than the International Space Station's orbital speed. Over 20,000 years, it has inflated to a radius of about 1.5×$10^{18}$ cm, roughly 100 times the distance from the Sun to Earth.