3D mapping of the Wolf-Rayet nebula M1-67: clues for post-common envelope evolution in massive stars

TL;DR

This study provides a detailed 3D morphological and kinematic analysis of the Wolf-Rayet nebula M1-67, supporting a common envelope origin for the nebula and its progenitor star WR124, and challenges previous bow shock interpretations.

Contribution

It introduces a comprehensive 3D model of M1-67 using high-resolution spectroscopic data and SHAPE modeling, revealing complex bipolar structures and supporting a common envelope formation scenario.

Findings

M1-67 has a complex bipolar 3D structure with concentric shells and jets.

The nebula likely formed through a common envelope event approximately 12,000 years ago.

The data contradict previous bow shock hypotheses for M1-67's morphology.

Abstract

We present a 3D mapping of the Wolf-Rayet (WR) nebula M1-67 around WR124. We obtained high-resolution San Pedro M\'{a}rtir (SPM) Manchester Echelle Spectrograph (MES) observations along 17 long-slit positions covering all morphological features in M1-67. We are able to unveil the true morphology of M1-67 and its kinematics by interpreting the SPM MES observations by means of the 3D modelling tool for Astrophysics SHAPE. Our SHAPE model that best reproduces the SPM MES data includes three concentric bipolar structures composed by a hollow ellipsoidal structure and a torus. In addition, the model requires the presence of expanding jets and broken blisters in order to reproduce specific spectral features. Our results are consistent with the idea that M1-67 and its progenitor star WR124 have formed through a common envelope scenario that occurred 11.8$^{+4.6}_{-0.8}$ kyr ago. Our bipolar model strongly questions previous suggestions of the presence of a bow shock structure surrounding M1-67. We interpret that the bright structures detected in the spectra extracted from the central regions are produced by wind compression at the receding region of the innermost structure in M1-67. Furthermore, WR124 is moving through a low-density region above the Galactic plane that has negligibly affected the formation history of M1-67.