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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

It is not known whether the original carriers of Earth's nitrogen weremolecular ices or refractory dust. To investigate this question, we have useddata and results of Herschel observations towards two protostellar sources: thehigh-mass hot core of Orion KL, and the low-mass protostar IRAS 16293-2422.Towards Orion KL, our analysis of the molecular inventory of Crockett et al.(2014) indicates that HCN is the organic molecule that contains by far the mostnitrogen, carrying $74_{-9}^{+5}\%$ of nitrogen-in-organics. Following thisevidence, we explore HCN towards IRAS 16293-2422, which we consider a solaranalog. Towards IRAS 16293-2422, we have reduced and analyzed Herschel spectraof HCN, and fit these observations against "jump" abundance models of IRAS16293-2422's protostellar envelope. We find an inner-envelope HCN abundance$X_{\textrm{in}} = 5.9\pm0.7 \times 10^{-8}$ and an outer-envelope HCNabundance $X_{\textrm{out}} = 1.3 \pm 0.1 \times 10^{-9}$. We also find thesublimation temperature of HCN to be $T_{\textrm{jump}} = 71 \pm 3$~K; thismeasured $T_{\textrm{jump}}$ enables us to predict an HCN binding energy$E_{\textrm{B}}/k = 3840 \pm 140$~K. Based on a comparison of the HCN/H2O ratioin these protostars to N/H2O ratios in comets, we find that HCN (and, byextension, other organics) in these protostars is incapable of providing thetotal bulk N/H2O in comets. We suggest that refractory dust, not molecularices, was the bulk provider of nitrogen to comets. However, interstellar dustis not known to have 15N enrichment, while high 15N enrichment is seen in bothnitrogen-bearing ices and in cometary nitrogen. This may indicate that these15N-enriched ices were an important contributor to the nitrogen inplanetesimals and likely to the Earth.

Exploring the Origins of Earth's Nitrogen: Astronomical Observations of Nitrogen-bearing Organics in Protostellar Environments