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arXiv · 2002.06045

No nitrogen fractionation on 600 au scale in the Sun progenitor analogue OMC-2 FIR4

F. Fontani·G. Quaia·C. Ceccarelli·L. Colzi·A. Lopez-Sepulcre·C. Favre·C. Kahane·P. Caselli·C. Codella·L. Podio·S. Viti
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Abstract

We show the first interferometric maps of the 14N/15N ratio obtained with the Atacama Large Millimeter Array (ALMA) towards the Solar-like forming protocluster OMC-2 FIR4. We observed N2H+, 15NNH+, N15NH+ (1-0), and N2D+ (2-1), from which we derive the isotopic ratios 14N/15N and D/H. The target is one of the closest analogues of the environment in which our Sun may have formed. The ALMA images, having synthesised beam corresponding to ~600 au, show that the emission of the less abundant isotopologues is distributed in several cores of ~10" (i.e. ~0.02~pc or 4000 au) embedded in a more extended N2H+ emission. Overall, our results indicate that: (1) 14N/15N does not change across the region at core scales, and (2) 14N/15N does not depend on temperature variations. Our findings also suggest that the 14N/15N variations found in pristine Solar System objects are likely not inherited from the protocluster stage, and hence their reason has to be found elsewhere.

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F. Fontani, G. Quaia, C. Ceccarelli, L. Colzi, A. Lopez-Sepulcre, C. Favre, C. Kahane, P. Caselli, C. Codella, L. Podio, S. Viti. 2020-02-14. No nitrogen fractionation on 600 au scale in the Sun progenitor analogue OMC-2 FIR4. https://doi.org/10.1093/mnras/staa481

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