Photonic spectro-interferometry with SCExAO/FIRST at the Subaru Telescope: towards H-alpha imaging of protoplanets

TL;DR

This paper discusses the development and on-sky testing of FIRST, a high-resolution spectro-interferometer at Subaru, optimized for detecting H-alpha emission from accreting exoplanets, advancing direct imaging capabilities.

Contribution

It introduces recent upgrades to FIRST, including a new spectrograph optimized for H-alpha detection, demonstrating improved on-sky performance for exoplanet characterization.

Findings

Bright companions detectable down to 0.25lambda/D

Successful integration of a new spectrograph for H-alpha

Enhanced sensitivity to pupil phase discontinuities

Abstract

FIRST is a post Extreme Adaptive-Optics (ExAO) spectro-interferometer operating in the Visible (600-800 nm, R~400). Its exquisite angular resolution (a sensitivity analysis of on-sky data shows that bright companions can be detected down to 0.25lambda/D) combined with its sensitivity to pupil phase discontinuities (from a few nm up to dozens of microns) makes FIRST an ideal self-calibrated solution for enabling exoplanet detection and characterization in the future. We present the latest on-sky results along with recent upgrades, including the integration and on-sky test of a new spectrograph (R~3,600) optimized for the detection of H-alpha emission from young exoplanets accreting matter.