Probing Outflow Activity in Very Low Mass Objects and Brown Dwarfs


Emma Whelan, Tom Ray, Francesca Bacciotti, Antonella Natta, Ray Jayawardhana


Stellar nurseries are the birth places of not only low to high mass stars but very low mass (VLM)and sub-stellar objects such as Brown Dwarfs (BDs), also. Numerous studies have shown that VLMOs and BDs are strong accretors and that in some cases they have a T Tauri like accretion phase. To date any hint that outflows may also be a feature of VLMOs or BDs has only come from the detection of optical FELs in their spectra. That the outflow phenomenon should be a common occurrence amongst protostellar and sub-stellar sources, or that this phenomenon should manifest itself in a similar manner for all objects, is not obvious a priori. Hence a fundamental question that must be answered deals with whether outflows are also launched by newborn objects in the very low mass to sub-stellar regimes and the possible forms in which this phenomenon may manifest itself. These questions ultimately address the universality of the outflow phenomenon and any discovery that BDs for example, too are associated with outflows, would extend the mass range, over which the jet mechanism operates to nearly 10 orders of magnitude. Here I shall review what is known to date about the forbidden emission line (FEL) spectra of VLMOs and BDs and in particular discuss how the important technique of spectro-astrometry is used to probe the FEL regions of newborn objects in the low mass to sub-stellar regimes. Integral Field Spectroscopy and adaptive optics can also play a vital role when it comes to resolving the FEL regions of objects not as yet proven to drive outflows and indeed there is potential for developing spectro-astrometry to a 2D form using an IFU.