Probing outflow activity in very low mass stars and brown dwarfs

摘要

The discovery that newborn very low mass stars and brown dwarfs have optical forbidden line spectra similar to low mass young stars was a strong indication that these objects can also launch outflows. Forbidden lines are the traditional tracers of outflow activity in young stars and observations at these wavelengths have contributed much to the understanding of outflows. However in the case of brown dwarfs, the forbidden emission line regions observed are not well resolved spatially. Thus, their origin in an outflow could not be confirmed. Here, the technique of spectro-astrometry as a means of spatially probing the forbidden emission line regions of very low mass stars and brown dwarfs is introduced. Indeed spectro-astrometric data presented here demonstrates, for the first time, that young brown dwarfs that are actively accreting can drive outflows. Also discussed is the important role adaptive optics will play when it comes to spatially resolving the forbidden emission line regions of sub-stellar objects and the potential for developing spectro-astrometry to a 2D form through integral field spectroscopy.