| Issue |
A&A
Volume 688, August 2024
|
|
|---|---|---|
| Article Number | A118 | |
| Number of page(s) | 22 | |
| Section | Interstellar and circumstellar matter | |
| DOI | https://doi.org/10.1051/0004-6361/202348529 | |
| Published online | 13 August 2024 | |
Deuterium fractionation of the starless core L 1498★
1
Academia Sinica Institute of Astronomy and Astrophysics (ASIAA),
No. 1, Section 4, Roosevelt Road,
Taipei
10617,
Taiwan
e-mail: shengjunlin@asiaa.sinica.edu.tw
2
Institute of Astronomy, National Tsing Hua University (NTHU),
No. 101, Section 2, Kuang-Fu Road,
Hsinchu
30013,
Taiwan
3
Center for Informatics and Computation in Astronomy (CICA),
NTHU, No. 101, Section 2, Kuang-Fu Road,
Hsinchu
30013,
Taiwan
e-mail: slai@phys.nthu.edu.tw
4
LERMA & UMR8112 du CNRS, Observatoire de Paris, PSL University, Sorbonne Universités, CNRS,
75014
Paris,
France
5
Institut de Radioastronomie Millimétrique (IRAM),
300 rue de la Piscine,
38400
Saint-Martin-d’Hères,
France
Received:
9
November
2023
Accepted:
21
May
2024
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 N2H+ 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-H2D+, N2D+, 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-H2D+ (110−111) detection toward L 1498. We find a peak molecular hydrogen density of 1.6−0.3+3.0 × 105 cm−3, a temperature of 7.5−0.5+0.7 K, and a N2H+ 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.
Key words: ISM: abundances / ISM: clouds / ISM: kinematics and dynamics / ISM: structure / ISM: individual objects: LDN 1498
Publisher note: A missing grant number was added on 30 August 2024.
The reduced CFHT J, H, Ks-band images are available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/688/A118
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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