130 Stellar and planetary parameters

No detectable helium absorption is seen, as absorption depth is measured to -0.0025{+/-}0.0021, or 1.2{sigma} from a null detection. This nondetection follows our current understanding of decreasing stellar activity (and thus high-energy radiation) with age. We use a 1D isothermal Parker wind model to compare with our observations and find that our nondetection can best be explained with a low planetary mass-loss rate and high thermosphere temperature.

We explore our results within the context of the full sample of helium detections and nondetections to date. Surprisingly, comparing helium absorption with the stellar activity index logR'_HK_ reveals a large spread in the correlation between these two factors, suggesting that there are additional parameters influencing the helium absorption strength.