Deuterium fractionation of the starless core L 1498
Context . Molecular deuteration is commonly seen in starless cores and is expected to occur on a timescale comparable to that of the core contraction. Thus, the deuteration serves as a chemical clock, allowing us to investigate dynamical theories of core formation. Aims . We aim to provide a 3D clou...
Gespeichert in:
Veröffentlicht in: | Astronomy and astrophysics (Berlin) 2024-08, Vol.688, p.A118 |
---|---|
Hauptverfasser: | , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Context . Molecular deuteration is commonly seen in starless cores and is expected to occur on a timescale comparable to that of the core contraction. Thus, the deuteration serves as a chemical clock, allowing us to investigate dynamical theories of core formation.
Aims . We aim to provide a 3D cloud description for the starless core L 1498 located in the nearby low-mass star-forming region Taurus and explore its possible core formation mechanism.
Methods . We carried out nonlocal thermal equilibrium radiative transfer with multi-transition observations of the high-density tracer N 2 H + to derive the density and temperature profiles of the L 1498 core. By combining these observations with the spectral observations of the deuterated species, ortho-H 2 D + , N 2 D + , and DCO + , we derived the abundance profiles for the observed species and performed chemical modeling of the deuteration profiles across L 1498 to constrain the contraction timescale.
Results . We present the first ortho-H 2 D + (1 10 −1 11 ) detection toward L 1498. We find a peak molecular hydrogen density of 1.6 −0.3 +3.0 × 10 5 cm −3 , a temperature of 7.5 −0.5 +0.7 K, and a N 2 H + deuteration of 0.27 −0.15 +0.12 in the center.
Conclusions . We derived a lower limit of the core age for L 1498 of 0.16 Ma, which is compatible with the typical free-fall time, indicating that L 1498 likely formed rapidly. |
---|---|
ISSN: | 0004-6361 1432-0746 1432-0756 |
DOI: | 10.1051/0004-6361/202348529 |