2004ApJ...615..850M

Initial evidence of IR excess and disk mass accretion (strong Hα emission) around brown dwarfs (BDs) seems to indicate the existence of circumstellar disks around these substellar objects. Nothing is known at present about outflows that might be launched from BDs, although jets are typically associated with the accretion in the case of standard T Tauri star disks. In this paper we calculate the Hα emission of internal working surfaces produced by a radiative jet in a neutral and in a photoionized environment as a function of the jet parameters (the ejection velocity v_j, shock velocity v_s, mass-loss rate M{dot}, and radius r_jof the jet), and we provide estimates of the Hα luminosity for the parameters of ``standard'' Herbig-Haro (HH) jets from T Tauri stars and for the parameters expected for jets from BDs. Interestingly, we find that while the mass-loss rates associated with jets from BDs are 2 orders of magnitude lower than the mass-loss rates associated with ``standard'' HH jets (from T Tauri stars), their velocities are likely to be similar. Based on our calculations, we discuss the conditions in which jets from BDs can be detected, and we conclude that the Hα luminosities of internal working surfaces of jets from BDs in a photoionized environment should be only 1 order of magnitude lower than the Hα luminosities of T Tauri jets in a neutral environment.