Betelgeuse scope: Single-mode-fibers-assisted optical interferometer design for dedicated stellar activity monitoring

TL;DR

This paper proposes a low-cost, single-mode-fiber-assisted optical interferometer designed specifically for monitoring stellar activity, exemplified by Betelgeuse's recent brightness variations, enabling detailed surface and dust formation observations.

Contribution

It introduces a novel interferometer design utilizing polarization-maintaining fibers and active error correction for dedicated stellar activity monitoring.

Findings

Design of a 12-telescope interferometer on a radio dish

Implementation of fiber-based beam combination with vibration correction

Potential for real-time monitoring of stellar surface changes

Abstract

Betelgeuse has gone through a sudden shift in its brightness and dimmed mysteriously. This is likely caused by a hot blob of plasma ejected from Betelgeuse and then cooled to obscuring dust. If true, it is a remarkable opportunity to directly witness the formation of dust around a red supergiant star. Today's optical telescope facilities are not optimized for time-evolution monitoring of the Betelgeuse surface, so in this work, we propose a low-cost optical interferometer. The facility will consist of $12 \times 4$ inch optical telescopes mounted on the surface of a large radio dish for interferometric imaging; polarization-maintaining single-mode fibers will carry the coherent beams from the individual optical telescopes to an all-in-one beam combiner. A fast steering mirror assisted fiber injection system guides the flux into fibers. A metrology system senses vibration-induced piston errors in optical fibers, and these errors are corrected using fast-steering delay lines. We will present the design.