The Common Envelope Origins of the Fast Jet in the Planetary Nebula M 3–38

We present the analysis of Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía (MEGARA) high-dispersion integral field spectroscopic observations of the bipolar planetary nebula (PN) M 3–38. These observations unveil the presence of a fast outflow aligned with the symmetry axis of M 3–38 that expands with a velocity of up to ±225 km s−1. The deprojected space velocity of this feature can be estimated to be ≈320${}_{-60}^{+130}$ km s−1, which together with its highly collimated morphology suggests that it is one of the fastest jets detected in a PN. We have also used Kepler observations of the central star of M 3–38 to unveil variability associated with a dominant period of 17.7 days. We attribute this to the presence of a low-mass star with an orbital separation of ≈0.12–0.16 au. The fast and collimated ejection and the close binary system point toward a common envelope formation scenario for M 3–38.