Exocomet models in transit: light curve morphology in the optical -- near infrared wavelength range

TL;DR

This paper develops a method for simulating exocomet transit light curves across multiple wavelengths, demonstrating that multicolor photometry can effectively detect and characterize exocomets by revealing dust properties and tail effects.

Contribution

The paper introduces a novel approach for modeling exocomet transits with arbitrary dust distributions and analyzes their multicolor light curve signatures, enhancing detection and characterization techniques.

Findings

Multicolor photometry effectively detects exocomets.

Color variations reveal dust composition and size.

Wavelength dependence affects transit timing.

Abstract

Following the widespread practice of exoplanetary transit simulations, various presumed components of an extrasolar system can be examined in numerically simulated transits, including exomoons, rings around planets, and the deformation of exoplanets. Template signals can then be used to efficiently search for light curve features that mark specific phenomena in the data, and they also provide a basis for feasibility studies of instruments and search programs. In this paper, we present a method for exocomet transit light curve calculations using arbitrary dust distributions in transit. The calculations, spanning four distinct materials (carbon, graphite, pyroxene, and olivine), dust grain sizes ($100$\,nm -- $300$\,nm, $300$\,nm -- $1000$\,nm, and $1000$\,nm -- $3000$\,nm) encompass light curves in VRJHKL bands. We also investigated the behavior of scattering colors. We show that multicolor photometric observations are highly effective tools in the detection and characterization of exocomet transits. They provide information on the dust distribution of the comet (encoded in the light curve shape), while the color information itself can reveal the particle size change and material composition of the transiting material, in relation to the surrounding environment. We also show that the typical cometary tail can result in the wavelength dependence of the transit timing. We demonstrate that multi-wavelength observations can yield compelling evidence for the presence of exocomets in real observations.