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

Spectrally-resolved observations of three pure rotational lines of H$_2$,conducted with the EXES instrument on SOFIA toward the classic bow shock HH7,reveal systematic velocity shifts between the S(5) line of ortho-H$_2$ and thetwo para-H$_2$ lines [S(4) and S(6)] lying immediately above and below it onthe rotational ladder. These shifts, reported here for the first time, implythat we are witnessing the conversion of para-H$_2$ to ortho-H$_2$ within ashock wave driven by an outflow from a young stellar object. The observationsare in good agreement with the predictions of models for non-dissociative,C-type molecular shocks. They provide a clear demonstration of the chemicalchanges wrought by interstellar shock waves, in this case the conversion ofpara-H$_2$ to ortho-H$_2$ in reactive collisions with atomic hydrogen, andprovide among the most compelling evidence yet obtained for C-type shocks inwhich the flow velocity changes continuously.

SOFIA/EXES observations of warm H$_2$ at high spectral resolution: witnessing para-to-ortho conversion behind a molecular shock wave in HH7