ExoTOM: a target-observation-manager automating exoplanet transit follow-up

We present ExoTOM - a target-observation-manager automating exoplanet transit follow-up. ExoTOM is built upon the TOM-toolkit developed by Las Cumbres Observatory (LCO). ExoTOM keeps track of known transiting exoplanet targets (and candidates), automatically predicts their transit times and observability at several telescope sites, and plans and requests observations via the LCO observing portal API. Target selection can be constrained by magnitude, transit depth and manually set priorities. The recorded photometric data is then automatically retrieved and analyzed. A simple transit fit is performed using the batman transit modeling package. The data and analysis products can be accessed and edited via the ExoTOM web interface. An analysis procedure was developed to extract the cleanest possible transit light curves from the photometric data. The main challenge was to find the best radius for the aperture photometry and the best sample of reference stars to use for the differential photometry. The analysis procedure first removes outlier reference stars and frames and then uses a new algorithm to solve the discrete optimization problem of selecting the best reference stars and aperture. From January through September 2021, ExoTOM's automatic observation scheduling produced 18 whole transit observations and 14 more of just the ingress or egress. The targets were TESS objects of interest ranging from TESS magnitude 8.7 to 13.5 mag and transit depth 1.5 to 118 mmag. These observations were done on the 50cm Cassegrain telescope of the Institute of Astrophysics of the University of Göttingen.