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Seeds of Life in Space (SOLIS). II. Formamide in protostellar shocks: Evidence for gas-phase formation
- Source :
- Astronomy & Astrophysics (0004-6361), 605, L3, Astronomy & Astrophysics, Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2017, 605, pp.L3. ⟨10.1051/0004-6361/201731249⟩, Astronomy and Astrophysics-A&A, 2017, 605, pp.L3. ⟨10.1051/0004-6361/201731249⟩
- Publication Year :
- 2017
-
Abstract
- Context: Modern versions of the Miller-Urey experiment claim that formamide (NH$_2$CHO) could be the starting point for the formation of metabolic and genetic macromolecules. Intriguingly, formamide is indeed observed in regions forming Solar-type stars as well as in external galaxies. Aims: How NH$_2$CHO is formed has been a puzzle for decades: our goal is to contribute to the hotly debated question of whether formamide is mostly formed via gas-phase or grain surface chemistry. Methods: We used the NOEMA interferometer to image NH$_2$CHO towards the L1157-B1 blue-shifted shock, a well known interstellar laboratory, to study how the components of dust mantles and cores released into the gas phase triggers the formation of formamide. Results: We report the first spatially resolved image (size $\sim$ 9", $\sim$ 2300 AU) of formamide emission in a shocked region around a Sun-like protostar: the line profiles are blueshifted and have a FWHM $\simeq$ 5 km s$^{-1}$. A column density of $N_{\rm NH_2CHO}$ = 8 $\times$ 10$^{12}$ cm$^{-1}$, and an abundance (with respect to H-nuclei) of 4 $\times$ 10$^{-9}$ are derived. We show a spatial segregation of formamide with respect to other organic species. Our observations, coupled with a chemical modelling analysis, indicate that the formamide observed in L1157-B1 is formed by gas-phase chemical process, and not on grain surfaces as previously suggested. Conclusions: The SOLIS interferometric observations of formamide provide direct evidence that this potentially crucial brick of life is efficiently formed in the gas-phase around Sun-like protostars.<br />7 pages, 1 table, 5 figures, A&A Letters, in press
- Subjects :
- Formamide
Abundance (chemistry)
Direct evidence
Stars: formation
FOS: Physical sciences
Context (language use)
Astrophysics
ISM: molecule
01 natural sciences
chemistry.chemical_compound
0103 physical sciences
Protostar
molecule [ISM]
010303 astronomy & astrophysics
ISM: jets and outflow
formation [Stars]
ComputingMilieux_MISCELLANEOUS
Line (formation)
Earth and Planetary Astrophysics (astro-ph.EP)
ISM: individual objects: L1157-B1
ISM: jets and outflows
ISM: molecules
Astronomy and Astrophysics
Space and Planetary Science
Physics
[PHYS]Physics [physics]
010308 nuclear & particles physics
jets and outflow [ISM]
individual objects: L1157-B1 [ISM]
Astronomy and Astrophysic
Stars
chemistry
Millimeter
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Astrophysics - Earth and Planetary Astrophysics
Subjects
Details
- Language :
- English
- ISSN :
- 00046361
- Database :
- OpenAIRE
- Journal :
- Astronomy & Astrophysics (0004-6361), 605, L3, Astronomy & Astrophysics, Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2017, 605, pp.L3. ⟨10.1051/0004-6361/201731249⟩, Astronomy and Astrophysics-A&A, 2017, 605, pp.L3. ⟨10.1051/0004-6361/201731249⟩
- Accession number :
- edsair.doi.dedup.....77b35689b0dd3997f2c1152f78d26748