Competing age solutions for Pismis 19

Determine whether Pismis 19 is a young cluster of approximately 49 Myr or an older system consistent with the substantially older ages favored by other catalogues, using spectroscopy of candidate members and star-by-star extinction corrections.

Background

Pismis 19 exhibits severe disagreement among published age estimates, ranging from approximately 49 Myr in the present analysis to approximately 112–123 Myr and nearly 1 Gyr in other catalogues. Differential reddening, field contamination, unresolved pulsating stars, and discrepant distance estimates complicate interpretation of its colour–magnitude diagram.

The paper’s fit-reliability analysis identifies Pismis 19 as having one of the broadest age posteriors. The available data do not distinguish the young solution from the older alternatives, so the cluster’s age and evolutionary interpretation remain unresolved.

References

The fit-reliability diagnostics of Section~\ref{sec:fit_reliability} place Pismis~19 among the systems whose age posterior is widest, and what the present data cannot do is separate the young solution we recover from the older ones favoured by CG20 and K13. Spectroscopy of the brightest candidate members, combined with a star-by-star extinction correction, would settle the question.

— Honoring Paris Pişmiş' Legacy: Uniform Astrophysical Properties of 14 Understudied Clusters from Gaia DR3  (2609.19486 - Koç et al., 16 Sep 2026) in Section 6.1.19, “Pismis 19”