Detection of the cyanomidyl radical (HNCN): a new interstellar species with the NCN backbone

TL;DR

This study reports the first detection of the interstellar cyanomidyl radical (HNCN), revealing its presence in space and suggesting its role as a precursor to prebiotic molecules with the NCN backbone.

Contribution

First detection of HNCN in the interstellar medium using radio telescopes, expanding knowledge of reactive molecules in space.

Findings

HNCN detected in G+0.693-0.027 with specific transitions

Molecular abundance estimated at ~0.91×10^{-10}

HNCN likely produced by gas-phase chemistry

Abstract

We report here the first detection in the interstellar medium of the cyanomidyl radical (HNCN). Using the Yebes 40m and the IRAM 30m telescopes, we have targeted the doublets of the $N$=2$-$1, 4$-$3, 5$-$4, 6$-$5, and 7$-$6 transitions of HNCN toward the molecular cloud G+0.693-0.027. We have detected three unblended lines of HNCN, these are the $N$=6$-$5 doublet and one line of the $N$=4$-$3 transition. Additionally we present one line of the $N$=5$-$4 transition partially blended with emission from other species. The Local Thermodynamic Equilibrium best fit to the data gives a molecular abundance of (0.91$\pm$0.05)$\times$10$^{-10}$ with respect to H$_2$. The relatively low abundance of this species in G+0.693-0.027, and its high reactivity, suggest that HNCN is possibly produced by gas-phase chemistry. Our work shows that this highly reactive molecule is present in interstellar space, and thus it represents a plausible precursor of larger prebiotic molecules with the NCN backbone such as cyanamide (NH$_2$CN), carbodiimide (HNCNH) and formamidine (NH$_2$CHNH).