Presentation #133.06 in the session “Binary Stellar Systems 1”.
HS Hydra belongs to a rare group of short period eclipsing binaries observed to have rapidly changing inclinations. This evolution is due to a third star on an intermediate orbit, and results in significant differences in eclipse depths year-to-year. Zasche & Paschke (2012) revealed that HS Hydra’s eclipses were rapidly fading from view, predicting they would cease around 2022. Using 27 days of photometric data from Sector 009 of the Transiting Exoplanet Survey Satellite (TESS), we find that the primary eclipses for HS Hydra were only 0.0075 magnitudes in depth in March 2019. This data from TESS likely represents the last eclipses detected from HS Hydra. We also searched the Digitization of the Harvard Astronomical Plate Collection (DASCH) archive for historic data from the system. With a total baseline of over 125 years, this unique combination of datasets - from photographic plates to precision space-based photometry - allows us to trace the emergence and decay of eclipses from HS Hydra, and further constrain its evolution. We estimate eclipses for HS Hydra will end in Feb 2021, and will begin again in 2196.