The symbiotic and bipolar nebula M2-9: Morphological variability of the collimated ionized wind arising from the core

TL;DR

This study uses radio interferometry to analyze the central region of bipolar nebula M2-9, revealing a variable collimated ionized wind likely driven by a symbiotic binary system, enhancing understanding of nebular morphology and dynamics.

Contribution

It provides high-resolution radio images of M2-9's core, demonstrating morphological variability of the collimated wind and supporting the presence of a symbiotic binary system.

Findings

Detected elongated jet-like structure at 43 GHz

Observed morphological variability in the collimated wind

Supported the symbiotic binary system hypothesis

Abstract

We studied the central region of bipolar nebula M\,2-9 using radio-continuum observations obtained from the Jansky Very Large Array (JVLA) and the Atacama Large Millimeter Array (ALMA) interferometers. This work presents new images at $\sim$ 43 GHz ($\sim$ 7.0 mm) and $\sim$ 345 GHz ($\sim$ 0.9 mm) with angular resolutions of $\sim$ 0$\rlap{.}^{\prime\prime}$047 and 0$\rlap{.}^{\prime\prime}$09, respectively. The continuum emission at $\sim$ 43 GHz shows an elongated jet-like structure perpendicular to the $\sim$ 345 GHz observation. We conclude that both emissions could correspond to tracing an isothermal collimated fast wind with constant expansion velocity and being driven by the circumstellar ring traced by ALMA. Although this configuration has been discussed within the scope of planetary nebulae models, there is a remarkable fact: the collimated fast wind shows morphological spatial variability. This supports the idea of a symbiotic binary system within the innermost part of M\,2-9, which would be composed of a white dwarf and an AGB star. The latter could explain the mirror symmetry observed at larger scales due to their orbital motion.