English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

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

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