No nitrogen fractionation on 600 au scale in the Sun progenitor analogue OMC-2 FIR4 - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Monthly Notices of the Royal Astronomical Society Year : 2020

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

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, OMC-2 FIR4, is one of the closest analogues of the environment in which our Sun may have formed. The ALMA images, having synthesized beam of ∼1.5 arcsec × 1.8 arcsec, I.e. ∼600 au, show that the emission of the less abundant isotopologues is distributed in several cores of ∼10 arcsec (I.e. ∼0.02 pc or 4000 au) embedded in a more extended N2H+emission. We have derived that the 14N/15N ratio does not vary from core to core, and our interferometric measurements are also consistent with single-dish observations. We also do not find significant differences between the 14N/15N ratios computed from the two 15N-bearing isotopologues, 15NNH+ and N15NH+. The D/H ratio derived by comparing the column densities of N2D+and N2H+changes by an order of magnitude from core to core, decreasing from the colder to the warmer cores. 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 the reason has to be found elsewhere.
Fichier principal
Vignette du fichier
staa481.pdf (2.03 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

insu-03705212 , version 1 (22-07-2023)

Identifiers

Cite

F. Fontani, G. Quaia, C. Ceccarelli, L. Colzi, A. López-Sepulcre, et al.. No nitrogen fractionation on 600 au scale in the Sun progenitor analogue OMC-2 FIR4. Monthly Notices of the Royal Astronomical Society, 2020, 493, pp.3412-3421. ⟨10.1093/mnras/staa481⟩. ⟨insu-03705212⟩
23 View
6 Download

Altmetric

Share

Gmail Facebook X LinkedIn More