The International Beta Pic b Transit Campaign

Beta Pic b is the only extrasolar giant planet that is both directly imaged and has a near-edge-on orbit that permits a study of its circumplanetary environment via the transit technique once every 22 years. Based on the orbital elements determined via multi-epoch astrometry using the Gemini Planet Imager (Wang et al. 2016), we determined that the 1.2 au radius Hill sphere of the planet would begin transiting the stellar photosphere in April 2017, with closest approach to the planet occurring in late August 2017. Here we present an overview of multiple ground and spaced-based campaigns that monitored beta Pic spectroscopically and photometrically for over six months to search for the signatures of circumplanetary gas and dust. These efforts included HST/WFC3/UVIS photometry using spatial scanning that demonstrated absolute precision of roughly 0.1% in seven epochs of observation spread over 12 months. We also summarize the capabilities and results from campaigns conducted from South Africa and Australia (bRing, SALT/HRS), Antarctica (ASTEP, AST3), Chile (VLT/UVES, HARPS), as well as HST/COS and the BRITE nanosatellites from space. [This work benefited from NSF AST-1518332, NASA NNX15AC89G & NNX15AD95G/NEXSS, and HST-GO-14621/14894/15119/15396.]