Direct Imaging of Planet Transit Events

TL;DR

This paper discusses the potential of optical interferometry to directly image exoplanet transit events, enabling precise measurement of system parameters and planetary characteristics without relying on traditional photometry or spectroscopy.

Contribution

It introduces a novel technique using optical interferometers for direct imaging of exoplanet transits, allowing independent and potentially more accurate determination of planetary and system parameters.

Findings

Potential to measure transit parameters directly with interferometry

Ability to determine planetary radius independently of other methods

Extraction of wavelength-dependent planetary radius for atmospheric analysis

Abstract

Exoplanet transit events are attractive targets for the ultrahigh-resolution capabilities afforded by optical interferometers. The intersection of two developments in astronomy enable direct imaging of exoplanet transits: first, improvements in sensitivity and precision of interferometric instrumentation; and second, identification of ever-brighter host stars. Efforts are underway for the first direct high-precision detection of closure phase signatures with the CHARA Array and Navy Precision Optical Interferometer. When successful, these measurements will enable recovery of the transit position angle on the sky, along with characterization of other system parameters, such as stellar radius, planet radius, and other parameters of the transit event. This technique can directly determine the planet's radius independent of any outside observations, and appears able to improve substantially upon other determinations of that radius; it will be possible to extract wavelength dependence of that radius determination, for connection to characterization of planetary atmospheric composition & structure. Additional directly observed parameters - also not dependent on transit photometry or spectroscopy - include impact parameter, transit ingress time, and transit velocity.