The Constant‐Velocity Highly Collimated Outflows of the Planetary Nebula He 2‐90

We present high-dispersion echelle spectroscopic observations and anarrow-band [N II] image of the remarkable jet-like features of He 2-90. Theyare detected in the echelle spectra in the H-alpha and [N II] lines but not inother nebular lines. The [N II]/H-alpha ratio is uniformly high, ~1. Theobserved kinematics reveals bipolar collimated outflows in the jet-likefeatures and shows that the southeast (northwest) component expands towards(away from) the observer at a remarkably constant line-of-sight velocity,26.0+-0.5 km/s. The observed expansion velocity and the opening angle of thejet-like features are used to estimate an inclination angle of ~5 degrees withrespect to the sky plane and a space expansion velocity of ~290 km/s. Thespectrum of the bright central nebula reveals a profusion of Fe lines andextended wings of the H-alpha line, similar to those seen in symbiotic starsand some young planetary nebulae that are presumed to host a mass-exchangingbinary system. If this is the case for He 2-90, the constant velocity anddirection of the jets require a very stable dynamic system against precessionand warping.Comment: 8 pages (emulate ApJ), 5 figure, 1 tabl