Fontani, F;
Quaia, G;
Ceccarelli, C;
Colzi, L;
Lopez-Sepulcre, A;
Favre, C;
Kahane, C;
... Viti, S; + view all
(2020)
No nitrogen fractionation on 600 au scale in the Sun progenitor analogue OMC-2 FIR4.
Monthly Notices of the Royal Astronomical Society
, 493
(3)
pp. 3412-3421.
10.1093/mnras/staa481.
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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, 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.
| Type: | Article |
|---|---|
| Title: | No nitrogen fractionation on 600 au scale in the Sun progenitor analogue OMC-2 FIR4 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/staa481 |
| Publisher version: | http://dx.doi.org/10.1093/mnras/staa481 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Stars: formation, ISM: clouds, ISM: molecules |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10096924 |
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