Carbon Chain Molecules Toward Embedded Low-Mass Protostars
| Main Author: | Law, Charles |
|---|---|
| Format: | info publication-thesis Journal |
| Terbitan: |
, 2017
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/810174 |
Daftar Isi:
- Carbon chain molecules may be an important reservoir of reactive, volatile organics during planet formation. Carbon chains have been observed toward several low-mass young stellar objects (YSOs), but their typical abundances and chemical relationships in such sources are largely unconstrained. We present observations toward 16 deeply embedded (Class 0/I) low-mass protostars using the IRAM 30 m telescope. Carbon chains are found to be common at this stage of protostellar evolution. We detect CCS, CCCS, HC3N, HC5N, C3H, and C4H toward 94%, 44%, 81%, 38%, 88%, and 88% of sources, respectively. Median column densities derived using survival analysis range between 9.6×1010cm−2 (CCCS) and 1.4×1013cm−2 (C4H) and fractional abundances with respect to hydrogen range between 1.6×10−13 (CCCS) and 4.5×10−11 (C4H). Column densities for each molecule vary by one to two orders of magnitude across the sample. Median abundances in our low-mass YSOs are found to be underabundant compared to cold cloud cores, warm carbon chain chemistry (WCCC) sources, and warm-up models. With the exception of CCS and HC3N, we do not find significant correlations between molecules in different carbon chain families, indicative of the presence of several independent carbon chain formation chemistries. This correlation also implies that the production chemistry of sulfur-bearing carbon chains and cyanpolyynes, which are closely related in the cold cloud phase, continue to be linked in low-mass star formation.
- Astro 99