The Nature and Frequency of Outflows from Stars in the Central Orion Nebula Cluster

TL;DR

This study uses high-resolution Hubble images to analyze the motions and origins of shocks from young stars in the Orion Nebula, revealing new Herbig-Haro objects and complex outflow patterns.

Contribution

It doubles the known Herbig-Haro objects in the Orion Nebula and uncovers multiple outflows from single stars, providing detailed insights into star formation processes.

Findings

Many shocks originate from a few stars, notably COUP 666.

Multiple outflows from single stars explain shock alignments and velocities.

Two regions have optical outflows without identified sources.

Abstract

Recent Hubble Space Telescope images have allowed the determination with unprecedented accuracy of motions and changes of shocks within the inner Orion Nebula. These originate from collimated outflows from very young stars, some within the ionized portion of the nebula and others within the host molecular cloud. We have doubled the number of Herbig-Haro objects known within the inner Orion Nebula. We find that the best-known Herbig-Haro shocks originate from a relatively few stars, with the optically visible X-ray source COUP 666 driving many of them. While some isolated shocks are driven by single collimated outflows, many groups of shocks are the result of a single stellar source having jets oriented in multiple directions at similar times. This explains the feature that shocks aligned in opposite directions in the plane of the sky are usually blue shifted because the redshifted outflows pass into the optically thick Photon Dominated Region behind the nebula. There are two regions from which optical outflows originate for which there are no candidate sources in the SIMBAD data base.