Reply to Desch et al. (2021) on "Breakup of a long-period comet as the origin of the dinosaur extinction"

TL;DR

This paper defends the hypothesis that a tidally disrupted long-period comet could have caused the dinosaur extinction, showing that such events increase impact rates sufficiently to match the Chicxulub crater's age.

Contribution

It demonstrates that tidal disruption of long-period comets significantly raises impact probabilities, supporting a cometary origin for the Chicxulub impact.

Findings

Tidal disruption produces multiple fragments crossing Earth's orbit.

Impact rate from disrupted comets aligns with Chicxulub crater age.

Uncertainty in fragment number does not negate the cometary hypothesis.

Abstract

We reply to criticisms by Desch et al. (2021) regarding our Scientific Reports paper, "Breakup of a long-period comet as the origin of the dinosaur extinction." 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. Our work demonstrates 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 greatly increases the impact rate of long-period comets capable of producing Chicxulub, making it consistent with the age of the Chicxulub impact crater. Our results are subject to an uncertainty in the number of fragments produced in the breakup event that leaves the conclusion of a cometary origin being more likely than an asteroidal one unchanged.