Observational signatures of the giant planets collisions

TL;DR

This paper explores the observable signals from collisions of giant exoplanets, including optical flashes and radio bursts, estimating their occurrence rates and detectability with current telescopes.

Contribution

It provides new estimates of collision rates and predicts specific electromagnetic signatures, such as optical flashes and radio bursts, from giant planet collisions.

Findings

Collision rate estimated at 0.01-1 per year in the Galaxy.

Optical and UV flashes are produced during collisions.

Radio bursts with flux ~30mJy at 3GHz are possible.

Abstract

We consider observational signatures of the collisions and partial destructions of giant exoplanets at the chaotic stage of the planetary systems evolution. The rate of these collisions in the Galaxy is estimated to be ~0.01-1 per yr. In the inelastic collision with a small relative velocity and small impact parameter, the planets may sufficiently lose their kinetic energy and merge together. Otherwise, if the planet is experienced a shallow tangential collision, it flews safety away. At the same time, the planets loss some part of their gas envelopes during mutual collisions. Collisions of the giant planets must be accompanied also by the radiation of energy from the radio to optical bands. The optical and near UV flashes result from the collision heating of the planet surface layers. Additionally, the collision compression and collapse of the powerful magnetosphere of giant planets are possible, with a successive generation of the radio bursts. According to our estimations, the corresponding rate the radio bursts is ~0.01-1 bursts per year with the maximum spectral flux ~30mJy at the frequencies ~3GHz and with a duration of the each burst ~1.5 hours. These signals are available for registration by the existing radio telescopes.