Breakup of a Long-Period Comet as the Origin of the Dinosaur Extinction

TL;DR

This paper proposes that the breakup of long-period comets due to tidal disruption near the Sun increased impact rates, explaining the origin of the Chicxulub impactor linked to the dinosaur extinction.

Contribution

It introduces a novel hypothesis that tidal disruption of long-period comets can account for the Chicxulub impactor's origin, aligning impact rates with geological evidence.

Findings

Tidal disruption produces smaller comet fragments crossing Earth's orbit.

This process increases impact rates by an order of magnitude.

It explains the composition and timing of the Chicxulub impact crater.

Abstract

The origin of the Chicxulub impactor, which is attributed as the cause of the K/T mass extinction event, is an unsolved puzzle. The background impact rates of main-belt asteroids and long-period comets have been previously dismissed as being too low to explain the Chicxulub impact event. Here, we show that a fraction of long-period comets are tidally disrupted after passing close to the Sun, each producing a collection of smaller fragments that cross the orbit of Earth. This population could increase the impact rate of long-period comets capable of producing Chicxulub impact events by an order of magnitude. This new rate would be consistent with the age of the Chicxulub impact crater, thereby providing a satisfactory explanation for the origin of the impactor. Our hypothesis explains the composition of the largest confirmed impact crater in Earth's history as well as the largest one within the last million years. It predicts a larger proportion of impactors with carbonaceous chondritic compositions than would be expected from meteorite falls of main-belt asteroids.