Abstract

In this talk, I will focus on the methods for optimizing the ground-based photometric precision for observing late M and L-type stars. Specifically, I will discuss a photometric atmospheric correction method and share the lessons learned from introducing an InGaAs-based instrument to the SPECULOOS Southern Observatory (SSO). The correction method targeted the induced effects from varying precipitable water vapor (PWV) in our atmosphere, on differentially resolved light curves. This work successfully reduced false variability of time-series data from late M and L-type stars on both long and short timescales, to the extent of removing false transit features. Parallel to this work, a feasibility study was conducted to introduce a new near-infrared instrumentation to SSO . The goal was to achieve better photometric precision than the existing CCD Si-based instrumentation while minimizing the induced effects of PWV variability. An InGaAs-based instrument, sensitive up to 1.62 μm, was identified. Additionally, a custom wide-pass filter called zYJ was designed and manufactured to form SPeculoos’ Infra-Red photometric Imager for Transits (SPIRIT). These results open up a new avenue for ground-based near-infrared robotic exoplanet transit surveys, as well as similar time-series focused astronomy. In conclusion, I suggest viable routes to further improve the photometric precision of such new instrumentation.