Evolutionary status of Pismis 8

Determine the evolutionary status and age of Pismis 8 by resolving the discrepancy between the older Gaia DR3 isochrone solution of approximately 191 Myr and the substantially younger solutions reported by prior studies.

Background

The Bayesian analysis derives an age of approximately 191 Myr for Pismis 8, whereas multiple catalogue and dedicated photometric studies favor an age of roughly 5–50 Myr. The final Gaia DR3 member sample lacks prominent indicators expected for such a young population, including a clearly populated upper main sequence and pre-main-sequence sequence.

The paper attributes the ambiguity to sparse membership, possible field contamination, differential reddening, and the possible exclusion of bright candidate members during high-probability filtering. It therefore leaves the cluster’s evolutionary classification unresolved pending spectroscopic confirmation.

References

Consequently, the evolutionary status of Pismis~8 should be regarded as uncertain, and the older Bayesian solution presented here should be interpreted with caution until high-resolution spectroscopic membership confirmation becomes available for the brightest candidate stars.

— Honoring Paris Pişmiş' Legacy: Uniform Astrophysical Properties of 14 Understudied Clusters from Gaia DR3  (2609.19486 - Koç et al., 16 Sep 2026) in Section 6.1.8, “Pismis 8”