MIRAC-5 on the MMT with MAPS: annular groove phase mask N-band coronagraphic upgrade

TL;DR

This paper discusses an upgrade to the MIRAC-5 coronagraph system on the MMT telescope, integrating advanced adaptive optics and phase mask technology to enhance exoplanet imaging capabilities in the mid-infrared.

Contribution

The paper introduces a new coronagraphic upgrade with an annular groove phase mask and optimized Lyot Stop, improving high-contrast imaging for exoplanet studies using the MMT's adaptive optics system.

Findings

Preliminary characterization of AGPM's on-axis source rejection.

Design of an optimized Lyot Stop for improved contrast.

System overview and performance metrics aligned with scientific goals.

Abstract

We describe the coronagraphic upgrade underway for the Mid-Infrared Array Camera-5 (MIRAC-5) to be used with the 6.5-m MMT telescope utilizing the new MMT Adaptive optics exoPlanet characterization System (MAPS). Mid-IR ground-based coronagraphic adaptive-optics-assisted imaging can be a powerful tool for characterizing exoplanet atmospheres and studying protoplanets in formation within circumstellar disks around young stars. In addition to enabling ground-based observations of bright targets in the background limit, high actuator density 1-2 kHz adaptive optics systems can be competitive with JWST in the contrast limit. We have procured an annular groove phase mask (AGPM) and performed preliminary characterization of its on-axis source rejection as a function of wavelength. We present an optimized Lyot Stop design for use with the AGPM using the High-contrast End-to-End Performance Simulator (HEEPS). Future work includes implementing the Quadrant Analysis of Coronagraphic Images for Tip-tilt Sensing (QACITS) control loop algorithm with MAPS. We present the system overview, pupil mask design, and expected performance metrics aligned with our scientific goals, building upon recent advances with MIRAC-5 (Bowens et al. 2025) and MAPS.