New white dwarfs for the stellar initial mass-final mass relation

TL;DR

This study identifies new white dwarf members in open clusters to refine the stellar initial mass-final mass relation, revealing a flatter relation at certain masses and discovering a potentially most massive cluster white dwarf.

Contribution

It reports the discovery of new white dwarfs in clusters and provides insights into the shape of the initial mass-final mass relation at intermediate stellar masses.

Findings

Four white dwarfs consistent with cluster membership identified.

The white dwarf masses suggest a flatter initial mass-final mass relation between 4.5 and 6.5 solar masses.

Potentially the most massive cluster white dwarf found to date, at about 1.1 solar masses.

Abstract

We present the preliminary results of a survey of the open clusters NGC3532 and NGC2287 for new white dwarf members which can help improve understanding of the form of the upper end of the stellar initial mass-final mass relation. We identify four objects with cooling times, distances and proper motions consistent with membership of these clusters. We find that despite a range in age of ~100Myr the masses of the four heaviest white dwarfs in NGC3532 span the narrow mass interval M~0.9-1.0Msolar suggesting that the initial mass-final mass relation is relatively flatter over 4.5Msolar <~ M_init <~ 6.5Msolar than at immediately lower masses. Additionally, we have unearthed WD J0646-203 which is possibly the most massive cluster white dwarf identified to date. With M~1.1Msolar it seems likely to be composed of ONe and has a cooling time consistent with it having evolved from a single star.