Classical T Tauri-like Outflow Activity in the Brown Dwarf Mass Regime

TL;DR

This study confirms that brown dwarfs exhibit classical outflow activity similar to low-mass stars, with new outflows discovered and detailed analysis showing scaled-down jet features and asymmetries.

Contribution

The paper reports the discovery of two new brown dwarf outflows and compares their properties to those of classical T Tauri stars, demonstrating scaled-down jet activity at the lowest masses.

Findings

Discovered two new brown dwarf outflows with detailed velocity and orientation measurements.

Observed asymmetry in outflow lobes, similar to low-mass protostellar jets.

Supported the idea that brown dwarf outflows are scaled-down versions of stellar jets.

Abstract

Over the last number of years spectroscopic studies have strongly supported the assertion that protostellar accretion and outflow activity persists to the lowest masses. In this paper we present the results of our latest investigation of brown dwarf (BD) outflow activity and report on the discovery of two new outflows. Here ISO-Oph 32 is shown to drive a blue-shifted outflow with a radial velocity of 10-20 km/s and spectro-astrometric analysis constrains the position angle of this outflow to 240 +/- 7 degrees. The BD candidate ISO-Cha1 217 is found to have a bipolar outflow bright in several key forbidden lines (radial velocity = -20 km/s, +40 km/s) and with a PA of 190-210 degrees. A striking feature of the ISO-Cha1 217 outflow is the strong asymmetry between the red and blue-shifted lobes. This asymmetry is revealed in the relative brightness of the two lobes (red-shifted lobe is brighter), the factor of two difference in radial velocity (the red-shifted lobe is faster) and the difference in the electron density (again higher in the red lobe). Such asymmetries are common in jets from low mass protostars and the observation of a marked asymmetry at such a low mass supports the idea that BD outflow activity is scaled down from low mass protostellar activity. In addition to presenting these new results, a comprehensive comparison is made between BD outflow activity and jets launched by CTTSs. In particular, the application of current methods for investigating the excitation conditions and mass loss rates in CTT jets to BD spectra is explored.