Discovery of new embedded Herbig-Haro objects in the ρ Ophiuchi dark cloud

Abstract

We report here the discovery of a 30″-chain of embedded Herbig-Haro (HH) objects in the ρ Ophiuchi dark cloud. These HH objects were first detected during a deep KS-band observation (completeness magnitude for point source ∼19) made with NTT/SOFI. We confirm their nature with follow-up observations made with H2 v = 1-0 S(1) narrow-band filter. We argue that they belong to two different jets emanating from two Class I protostars: the main component of the recently resolved subarcsecond radio binary YLW15 (also called IRS43), and IRS54. We propose also to identify the [S II] knot HH224NW1 (Gómez et al. 1998) as emanating from a counterjet of YLW15. The alignment between these HH objects and the thermal jet candidate found in YLW15 by Girart et al. (2000) implies that this jet is not precessing at least on timescale ∼(2-4)×104 yr.