The HAges Catalog: Stellar Ages for High Priority HWO Target Stars

Precise stellar ages (uncertainties 1 Gyr, or about 20% at solar age) are required to discern evolutionary trends in atmospheric biosignatures of terrestrial habitable zone exoplanets surveyed by the Habitable Worlds Observatory (HWO) and will aid in constraining planetary interior evolution and target prioritization. We present a catalog of stellar ages for Tier 1 and Tier 2 targets in the HWO Target Stars and Systems (TSS) sub-working group's TSS25 list, compiling published literature ages derived from high-precision methods. The sample comprises 659 stars likely to be observed by HWO, independent of the final mission architecture. This initial catalog focuses on asteroseismology and gyrochronology, which can achieve about 20% precision for the majority of these stars. We find that only about 5% of the sample have asteroseismic ages and about 20% have gyrochronal ages, with just about 2% having constraints from both methods. For stars with multiple published measurements, the median reported statistical uncertainties are slightly smaller than the systematic uncertainties: about 9% versus about 12% for asteroseismology and about 16% versus about 18% for gyrochronology. The scarcity of precise stellar ages in this sample highlights the need for a concerted effort to obtain robust age constraints in advance of HWO; this catalog is intended as a living resource that will be regularly updated in the lead-up to the mission.