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Tracing the cold an...
Tracing the cold and warm physico-chemical structure of deeply embedded protostars: IRAS 16293−2422 versus VLA 1623−2417 N.
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- Murillo, N. M. (författare)
- Universiteit Leiden (UL),Leiden University (UL)
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- van Dishoeck, E. F. (författare)
- Max-Planck-Institut für extraterrestrische Physik,Max Planck Institute for Extraterrestrial Physics,Universiteit Leiden (UL),Leiden University (UL)
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- van der Wiel, M. H. D. (författare)
- Netherlands Institute for Radio Astronomy (ASTRON),Köpenhamns universitet,University of Copenhagen
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- Jorgensen, J. K. (författare)
- Köpenhamns universitet,University of Copenhagen
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- Drozdovskaya, M. N. (författare)
- Köpenhamns universitet,University of Copenhagen,Universiteit Leiden (UL),Leiden University (UL)
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- Calcutt, Hannah, 1988 (författare)
- Köpenhamns universitet,University of Copenhagen
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- Harsono, D. (författare)
- Universiteit Leiden (UL),Leiden University (UL)
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(creator_code:org_t)
- 2018-09-27
- 2018
- Engelska.
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 617
- Relaterad länk:
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https://www.aanda.or...
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https://doi.org/10.1...
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https://research.cha...
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Abstract
Ämnesord
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- Context. Much attention has been placed on the dust distribution in protostellar envelopes, but there are still many unanswered questions regarding the physico-chemical structure of the gas. Aims. Our aim is to start identifying the factors that determine the chemical structure of protostellar regions, by studying and com- paring low-mass embedded systems in key molecular tracers. Methods. The cold and warm chemical structures of two embedded Class 0 systems, IRAS 16293−2422 and VLA 1623−2417 were characterized through interferometric observations. DCO+, N2H+, and N2D+ were used to trace the spatial distribution and physics of the cold regions of the envelope, while c−C3H2 and C2H from models of the chemistry are expected to trace the warm (UV-irradiated) regions. Results. The two sources show a number of striking similarities and differences. DCO+ consistently traces the cold material at the disk-envelope interface, where gas and dust temperatures are lowered due to disk shadowing. N2H+ and N2D+, also tracing cold gas, show low abundances toward VLA 1623−2417, but for IRAS 16293−2422, the distribution of N2D+ is consistent with the same chemical models that reproduce DCO+. The two systems show different spatial distributions c−C3H2 and C2H. For IRAS 16293−2422, c−C3H2 traces the outflow cavity wall, while C2H is found in the envelope material but not the outflow cavity wall. In contrast, toward VLA 1623−2417 both molecules trace the outflow cavity wall. Finally, hot core molecules are abundantly observed toward IRAS 16293−2422 but not toward VLA 1623−2417. Conclusions. We identify temperature as one of the key factors in determining the chemical structure of protostars as seen in gaseous molecules. More luminous protostars, such as IRAS 16293−2422, will have chemical complexity out to larger distances than colder protostars, such as VLA 1623−2417. Additionally, disks in the embedded phase have a crucial role in controlling both the gas and dust temperature of the envelope, and consequently the chemical structure. Key
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- astrochemistry - stars
- low-mass - ism
- individual objects
- iras 16293-2422 and vla1623-2417
- interferometric
- methods
- observational - techniques
- formation - stars
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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