Suitability of COTS InGaAs detectors for ground-based exoplanet detections around nearby M-dwarfs

Abstract

In the search for exoplanets, the TESS mission shifts much of the focus in transit detection towards observing nearby cool stars.1 Many of the M-dwarf systems identified can be followed up from the ground with meter class telescopes or smaller to confirm the presence of rocky planets.2, 3 However, while space-based missions can easily justify the expensive mercury cadmium telluride (HgCdTe) detectors that perform well at the emission peaks of M-dwarfs, ground based searches at small facilities with modest budget need an alternative.4 Deep depletion charged-coupled devices (CCDs) are commercially available, but do not have good sensitivity beyond 1000 nm. Commercial off the shelf (COTS) indium gallium arsenide (InGaAs) detectors offer an alternative, but work needs to be done to characterise them, and adapt them to astronomical use. Towards this effort, we code automation software in Python for a commercially available unit and test the performance for typical use in astronomical instruments. We also integrate a unit into a spectroscopy instrument and demonstrate it on sky at near-infrared (NIR) ranges.