The Planetary Nebula in the 500 Myr old Open Cluster M37

TL;DR

This paper confirms a rare planetary nebula in the open cluster M37, providing insights into stellar evolution, mass relations, and nebula visibility in clusters, with implications for understanding higher mass progenitors.

Contribution

It presents the third known planetary nebula in a Galactic open cluster, with detailed analysis confirming cluster membership and implications for stellar evolution models.

Findings

Confirmed planetary nebula in M37 with Gaia data

Progenitor star mass estimated at ~2.8 Msun

Largest kinematical age for a planetary nebula in a cluster

Abstract

We report confirmation of a large, evolved, bipolar planetary nebula and its blue, white dwarf central star as a member of the ~500 Myr old Galactic open star cluster M37 (NGC 2099). This is only the third known example of a planetary nebula in a Galactic open cluster and was found via our on-going program of identifying and studying planetary nebulae - open cluster associations. High confidence in the association comes from the consistent radial velocities and proper motions for the confirmed central star and cluster stars from Gaia, reddening agreement and location of the planetary nebula well within the tidal cluster boundary. Interestingly, all three Galactic examples have bipolar morphology and likely Type I chemistry, both characteristics of higher mass progenitors. In this case the progenitor star mass is in the mid-range of ~2.8 Msun. It provides a valuable, additional point on the key stellar initial-to-final mass relation independent of cluster white dwarf estimates and also falls in a gap in the poorly sampled mass region. This planetary nebula also appears to have the largest kinematical age ever determined and implies increased visibility lifetimes when they are located in clusters.