The role of FUV Pumping in exciting the [Oi] lines in Protostellar Disks and Winds

TL;DR

This paper investigates how FUV radiation influences the excitation of [Oi] emission lines in protostellar disks and winds, revealing that FUV pumping significantly affects line strengths and origins, depending on the model specifics.

Contribution

It demonstrates the importance of FUV pumping in exciting [Oi] lines and its impact on line characteristics in different protostellar models.

Findings

FUV pumping can significantly excite [Oi] lines at observed accretion luminosities.

The excitation mechanism varies with the hydrodynamical model used.

Line strengths and profiles are affected by including FUV pumping in simulations.

Abstract

We use Cloudy to re-examine excitation of [Oi] 6300 A and [Oi] 5577 A in the X-ray driven photo-evaporative wind models of Owen and collaborators, and in more recent magnetothermal models by Wang et al. We find that, at the measured accretion luminosities, the FUV radiation would populate the upper levels of the oxygen atom which would eventually contribute to the [Oi] lines. FUV pumping competes with collisions as an excitation mechanism of the [Oi] lines, and they each originate from a distinct region in the protostellar disk environment depending on the specifics of the hydrodynamical model that the simulation was based on. Consequently, the line strengths and shapes of [Oi] 6300 A and[Oi] 5577 A would be affected by the inclusion of FUV pumping in the radiation transport simulations.