Resolving the Multiple Outflows in the Egg Nebula with Keck II Laser Guide Star Adaptive Optics

TL;DR

This study uses Keck II laser guide star adaptive optics to obtain high-resolution images and spectroscopy of the Egg Nebula, revealing detailed morphology and kinematics of its dusty and molecular components, and clarifying its structure.

Contribution

The paper provides the first high-resolution imaging and spectral analysis of the Egg Nebula's dusty and molecular components, clarifying the nebula's morphology and kinematic properties.

Findings

Resolved dusty components in the central region.

Confirmed peak A is not a companion star.

Detected H2 emission velocities over 100 km/s.

Abstract

The Egg Nebula has been regarded as the archetype of bipolar proto-planetary nebulae, yet we lack a coherent model that can explain the morphology and kinematics of the nebular and dusty components observed at high-spatial and spectral resolution. Here, we report on two sets of observations obtained with the Keck Adaptive Optics Laser Guide Star: H to M-band NIRC2 imaging, and narrow bandpath K-band OSIRIS 3-D imaging-spectroscopy (through the H2 2.121micron emission line). While the central star or engine remains un-detected at all bands, we clearly resolve the dusty components in the central region and confirm that peak A is not a companion star. The spatially-resolved spectral analysis provide kinematic information of the H_2 emission regions in the eastern and central parts of the nebula and show projected velocities for the H_2 emission higher than 100 km/s. We discuss these observations against a possible formation scenario for the nebular components.