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 Plus annual

Presents the access of premium content as premium feature

Premium Content

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 annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We have detected CH$^{+}$ and CH molecular absorption lines from the youngcompact planetary nebula IC 4997 from high resolution optical spectra. Ahigh-resolution infra-red (H and K bands) spectrum provides detection of H$_2$emission lines amongst many other lines. The H$_2$ lines provide an excitationtemperature of 2100 K which may result from UV fluorescence in the envelope orfrom shocks formed at the interface between an expanding outflow of ionized gasand the neutral envelope ejected when the star was on the AGB. It is suggestedthat the CH$^+$ may result from the endothermic reaction C + H$_2$$\rightarrow$ CH$^+$ + H. Intriguingly, CH$^{+}$ and also CH show a higherexpansion velocity than H$_{\rm 2}$ emission suggesting they may be part of thepost-shocked gas.

Detection of CH$^{+}$, CH and H$_2$ molecules in the Young Planetary Nebula IC 4997