A Multi-Year Search For Transits Of Proxima Centauri. II: No Evidence For Transit Events With Periods Between 1-30 Days.

Using a global network of small telescopes, we have obtained light curves of Proxima Centauri at 329 observation epochs from 2006 to 2017. The planet Proxima b discovered by Anglada-Escude et al. (2016) with an orbital period of 11.186 d has an a priori transit probability of ~ 1.5%; if it transits, the predicted transit depth is about 5 millimagnitudes. In Blank et al. (2018), we analyzed 96 of our light curves that overlapped with predicted transit ephemerides from previously published tentative transit detections, and found no evidence in our data that would corroborate claims of transits with a period of 11.186 d. Here we broaden our analysis, using 262 high-quality light curves from our dataset to search for any periodic transit-like events over a range of periods from 1 to 30 d. We also inject a series of simulated planet transits and find that our data are sufficiently sensitive to have detected transits of 5 millimagnitude depth, with recoverability ranging from ~100% for orbital period of 1 d to ~20% for orbital period of 20 d for the parameter spaces tested. The recoverability specifically at the 11.186 d period of Proxima b is ~ 40% for the parameter spaces tested. While we are able to rule out virtually all transits of other planets at periods shorter than 5 d and depths greater than 5 millimagnitudes, we cannot rule out the possibility that transits of Proxima b are present but escaped detection. However, we are able to rule out virtually all transits of other planets at periods shorter than 5 d and depths greater than 3 millimagnitudes.