Searching for Atmospheric Outflow Variability in WASP-69b

XUV-driven photoevaporation is a leading hypothesis on the astrophysical processes that sculpt the observed distribution of short-period planetary radii. In recent years, direct evidence of atmospheric escape has been detected via in-transit transmission of the metastable He triplet near 10830 Å. Dozens of planets have been probed with this tracer, mostly as single-epoch snapshots. Since the stellar XUV that underlies planetary mass-loss is time-variable, it is necessary to understand the outflows’ responses to changes in the incident flux. Here, we report results from an ongoing longitudinal study to characterize the time-variability of WASP-69b’s atmospheric outflow. We obtained contemporaneous metastable He data from Palomar/WIRC along with X-ray and mid-UV data from the Swift Observatory. Together, these data lead to a comprehensive characterization of WASP-69b’s hydrodynamical state in the epoch of observation. By comparison to archival metastable He data and archival high-energy data from XMM-Newton, we assess the time variability of WASP-69b’s mass-loss rate on timescales commensurate with typical stellar activity cycles.