We present new radial velocity measurements of 586 stars in a one-degree field centred on the open cluster M46, and the planetary nebula NGC 2438 located within a nuclear radius of the cluster. The data are based on medium-resolution optical and near-infrared spectra taken with the AAOmega spectrograph on the Anglo-Australian Telescope. We find a velocity difference of about 30 km s -1 between the cluster and nebula, thus removing all ambiguities about the cluster membership of the planetary nebula caused by contradicting results in the literature. The line-of-sight velocity dispersion of the cluster is 3.9 ± 0.3 km s-1, likely to be affected by a significant population of binary stars.
- Open clusters and associations: general
- Planetary nebulae: general