YSO jets in the Galactic Plane from UWISH2: II - Outflow Luminosity and Length distributions in Serpens and Aquila

TL;DR

This study analyzes molecular hydrogen outflows in the Galactic Plane, revealing their properties, distribution, and implications for star formation, with a focus on intermediate-mass protostars and jet activity timescales.

Contribution

It provides the first statistical analysis of outflow luminosities, lengths, and distribution in Serpens and Aquila, highlighting their role in star formation and feedback.

Findings

Outflows sample intermediate-mass star formation.

Outflows contribute minimally to cloud turbulence.

Jet ages are around 10,000 years, with episodic ejections every 1,000 years.

Abstract

Jets and outflows accompany the mass accretion process in protostars and young stellar objects. Using a large and unbiased sample, they can be used to study statistically the local feedback they provide and the typical mass accretion history. Here we analyse such a sample of Molecular Hydrogen emission line Objects in the Serpens and Aquila part of the Galactic Plane. Distances are measured by foreground star counts with an accuracy of 25%. The resulting spacial distribution and outflow luminosities indicate that our objects sample the formation of intermediate mass objects. The outflows are unable to provide a sizeable fraction of energy and momentum to support, even locally, the turbulence levels in their surrounding molecular clouds. The fraction of parsec scale flows is one quarter and the typical dynamical jet age of the order of 1E4yrs. Groups of emission knots are ejected every 1E3yrs. This might indicate that low level accretion rate fluctuations and not FU-Ori type events are responsible for the episodic ejection of material. Better observational estimates of the FU-Ori duty cycle are needed.