An asymmetric outflow from the Herbig Ae star HD 163296

We present an observational picture of the HH 409 bipolar outflow including the detection of six previously unreported Herbig-Haro knots from the Herbig Ae star HD 163296. This study combines seven years of data from ground-based Fabry-Pe rot and HST coronagraphic imagery, as well as HST long-slit spectral imagery. The redshifted counterjet includes a chain of six Herbig-Haro knots spanning > 27 to the northeast (P.A. approximate to 42 degrees) of the source and has been active for > 80 yr. The brightest knot in the counterjet is HH 409 C, a low-excitation bow shock with a shock velocity Vs similar to 50 km s(-1) and total space motion V-jet approximate to 260 km s(-1). The presence of additional knots in the counterjet beyond the bow shock may indicate precession of the jet axis. The blueshifted jet includes two closely spaced knots within 10 and a distant bow shock (approximate to 21) southwest (P.A. approximate to 223 degrees) of the source. The brightest knot in the jet is HH 409 A, a higher excitation more bullet-like shock with V-s similar to 90 km s(-1) and Vjet approximate to 360 km s(-1). The average opening angles for both the jet and counterjet are similar, alpha(a) similar to 2 degrees, and consistent with opening angles of lower mass T Tauri stars. The mass-loss rates in both lobes of the flow, despite the asymmetry of the knots, are also comparable, M-out similar to 1.0 x 10(-8) M-circle dot yr(-1). This suggests that variations in the mass outflow rate are not more than a factor of similar to 2.