Supernova 1987A was a "failed supernova" twenty thousand years before its jet-driven explosion
This paper proposes that the progenitor of Supernova 1987A appeared as a "failed supernova" to equatorial observers for centuries due to obscuration by a binary-ejected ring, suggesting such events are actually Type II ILOTs rather than core-collapse failures, while also speculating that the Jittering Jets Explosion Mechanism explains the system's morphological misalignment.
Original paper licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
In the vast theater of the cosmos, massive stars live fast and die young, often ending their lives in spectacular explosions known as core-collapse supernovae. For decades, astronomers have debated exactly how these stars detonate. One school of thought suggests that a flood of ghostly particles called neutrinos provides the necessary push to blow the star apart. Another theory proposes that the star fires off powerful jets of material that punch through the core, driving the explosion. A third, more unsettling possibility has also been considered: that some massive stars simply collapse inward without exploding at all, fading away into a black hole in an event dubbed a "failed supernova." The star SN 1987A, which exploded in a nearby galaxy in 1987, remains the most famous and studied example of such an event. Its unique shape, featuring three glowing rings of gas, has long hinted at a complex history involving a companion star, but the precise story of what happened before the explosion has remained elusive.
A new study by Noam Soker offers a fresh perspective on this cosmic puzzle, suggesting that the history of SN 1987A might have fooled observers into thinking a "failed supernova" occurred, even though the star actually survived its pre-explosion phase. The research focuses on a dramatic event that took place roughly twenty thousand years before the star finally exploded. At that time, the star, which was likely in a binary system with a smaller companion, underwent a violent interaction that ejected a massive amount of material. This material formed a dense, flat ring around the star's equator, along with two fainter outer rings. Soker argues that for an observer standing in the plane of this ring, the star would have appeared to fade dramatically and turn red for hundreds of years. The dense ring of gas and dust would have blocked the direct view of the star, allowing only a tiny fraction of its light to reach the observer, mostly as scattered glow from the outer rings. To such a viewer, the star would seem to be dimming and dying, mimicking the signature of a failed supernova.
However, the paper clarifies that nothing actually failed. There was no core collapse and no black hole formed during this long period of dimming. Instead, the event was a type of intermediate-luminosity optical transient, a phenomenon where a star temporarily hides behind its own ejected debris. Over the course of a few hundred years, the outer rings became transparent enough to let more light through, and eventually, the inner ring cleared up as well. The progenitor star then brightened over a few thousand years to its normal luminosity, continuing until it finally exploded as a supernova two decades later. This finding supports the idea that many candidates previously thought to be failed supernovae might actually be stars simply obscured by their own ejected material, rather than stars that have collapsed into darkness.
The study also tackles a second mystery regarding the shape of the explosion. While the three rings of gas lie in a flat plane, the actual explosion that occurred in 1987 was not aligned with them; the blast was tilted at a significant angle, creating a bipolar structure that looks like a keyhole. If the companion star had simply spun up the core of the dying star, one might expect the explosion to align with the rings. Since it does not, Soker proposes a more complex scenario involving the jittering jets explosion mechanism. In this model, the explosion begins with chaotic jets firing in random directions. As the explosion progresses, the rotation of the star's core, which was spun up by the companion, eventually guides the final, most powerful jets into a fixed direction. This direction happens to be tilted relative to the rings, creating the misaligned, keyhole-shaped explosion we see today.
This research adds a layer of nuance to our understanding of how massive stars die. It suggests that the "failed supernovae" we might observe are not necessarily stars that have given up the ghost, but rather stars in the middle of a messy, dusty transition. By using the unique history of SN 1987A as a case study, the paper strengthens the argument that jet-driven explosions are a primary way these stars end their lives. It paints a picture of a star that, twenty thousand years before its final moment, hid behind a curtain of its own making, briefly deceiving the universe into thinking it had failed, before eventually revealing its true, explosive nature.
Drowning in papers in your field?
Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.