Original title: Near-Horizon Tidal Disruption Events
Yang Yang, Xian Chen · September 2026
When a star wanders too close to a supermassive black hole, intense gravity tears it apart. Usually, this happens far from the black hole's outer boundary, called the event horizon. But around huge, rapidly spinning black holes with masses of M_ullet \gtrsim 10^8 M_\odot, stars are ripped apart right near the horizon. Scientists call these "near-horizon tidal disruption events." To see how this extreme gravity works, the researchers mapped the paths of falling stellar material in spinning spacetime. They found that for stars on parabolic paths, up to \sim (90 \%-95 \%) of the debris either plunges straight into the black hole or flies away into space. Bound stars keep much more debris, leading to peak fallback rates that are higher and decay faster by factors of \sim 10^3. However, very low angular momentum causes debris loss that suppresses this peak. This rapid, altered fallback explains unusually bright events like ASASSN-15lh.
Imagine you are dropping a handful of marbles into a deep funnel. Normally, the marbles roll down the sides and fall into the hole at the bottom. But if the funnel is very wide and spinning fast, the marbles near the edge either get flung out or drop straight in, leaving only a few that spiral down slowly. Here, the funnel represents the gravity of a massive spinning object, the marbles are pieces of a disrupted star, and the few spiraling marbles correspond to debris that falls back quickly, producing a bright flash.
This work explains why some tidal disruption events are extraordinarily bright, like ASASSN-15lh, which standard models couldn't account for. It also gives astronomers a new tool to find massive, rapidly spinning black holes by looking for these fast, bright flares. Understanding these events helps probe the extreme gravity near a black hole's horizon.
The abstract doesn't explicitly state limitations, but the work is theoretical and focuses on a specific regime of rapidly spinning, very massive black holes. It does not provide direct observational evidence beyond explaining one event, ASASSN-15lh. The results depend on assumptions of Kerr spacetime and specific orbital types; other configurations are not explored.
Ask anything about this paper. Answers come from its abstract, and say so when the abstract doesn't cover your question.
Near-Horizon Tidal Disruption Events — Yang Yang, Xian Chen
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.