The HAges Catalog Public Release

The HAges Catalog is a compilation of stellar ages for the high-priority stars in tiers 1 and 2 of the Habitable Worlds Observatory Target Stars and Systems (TSS) sub-working group's TSS25 list (Tuchow et al. 2025). The current catalog contains published ages from asteroseismology and gyrochronology and is split into three separate tables that are available as downloadable CSV files:

• Overview: This table contains summary age statistics for each star in the TSS25 list and for each of the age-dating methods. This includes the average age, sample standard deviation, median age, the spread in the individual age measurements, and the number of individual age measurements.
• Asteroseismology: This table contains all the individual age measurements and reported statistical uncertainties for each star derived through asteroseismology, along with the references and additional information.
• Gyrochronology: This table contains all the individual age measurements and reported statistical uncertainties for each star derived through gyrochronology, along with the references and additional information.

Article Abstract:

Precise stellar ages (uncertainties ≲ 1 Gyr, or ~ 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 ~ 20% precision for the majority of these stars. We find that only ~ 5% of the sample have asteroseismic ages and ~ 20% have gyrochronal ages, with just ~ 2% having constraints from both methods. For stars with multiple published measurements, the median reported statistical uncertainties are slightly smaller than the systematic uncertainties: ~ 9% versus ~ 12% for asteroseismology and ~ 16% versus ~ 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.