Optically Thick Radio Cores of Narrow-Waist Bipolar Nebulae

TL;DR

This study searches for optically thick radio cores in narrow-waist bipolar nebulae, finding evidence of ionized jets in several objects, which may influence their bipolar morphology.

Contribution

First systematic radio survey of narrow-waist bipolar nebulae revealing potential ionized jets linked to nebula shaping.

Findings

Detection of compact radio cores with rising spectra in multiple nebulae.

Evidence supporting ionized jets as shaping mechanisms in bipolar nebulae.

Identification of specific nebulae with optically thick radio cores.

Abstract

We report our search for optically thick radio cores in sixteen narrow-waist bipolar nebulae. Optically thick cores are a characteristic signature of collimated ionized winds. Eleven northern nebulae were observed with the Very Large Array (VLA) at 1.3 cm and 0.7 cm, and five southern nebulae were observed with the Australia Telescope Compact Array (ATCA) at 6 cm and 3.6 cm. Two northern objects, 19W32 and M 1-91, and three southern objects, He 2-25, He 2-84 and Mz 3, were found to exhibit a compact radio core with a rising spectrum consistent with an ionized jet. Such jets have been seen in M 2-9 and may be responsible for shaping bipolar structure in planetary nebulae.