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Title: CONSTRAINING THE ABUNDANCES OF COMPLEX ORGANICS IN THE INNER REGIONS OF SOLAR-TYPE PROTOSTARS

Abstract

The high abundances of Complex Organic Molecules (COMs) with respect to methanol, the most abundant COM, detected toward low-mass protostars, tend to be underpredicted by astrochemical models. This discrepancy might come from the large beam of the single-dish telescopes, encompassing several components of the studied protostar, commonly used to detect COMs. To address this issue, we have carried out multi-line observations of methanol and several COMs toward the two low-mass protostars NGC 1333-IRAS 2A and -IRAS 4A with the Plateau de Bure interferometer at an angular resolution of 2″, resulting in the first multi-line detection of the O-bearing species glycolaldehyde and ethanol and of the N-bearing species ethyl cyanide toward low-mass protostars other than IRAS 16293. The high number of detected transitions from COMs (more than 40 methanol transitions for instance) allowed us to accurately derive the source size of their emission and the COM column densities. The COM abundances with respect to methanol derived toward IRAS 2A and IRAS 4A are slightly, but not substantitally, lower than those derived from previous single-dish observations. The COM abundance ratios do not vary significantly with the protostellar luminosity, over five orders of magnitude, implying that low-mass hot corinos are quite chemically richmore » as high-mass hot cores. Astrochemical models still underpredict the abundances of key COMs, such as methyl formate or di-methyl ether, suggesting that our understanding of their formation remains incomplete.« less

Authors:
;  [1]; ; ;  [2];  [3]
  1. Astrochemistry Laboratory and The Goddard Center for Astrobiology, Mailstop 691, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20770 (United States)
  2. Univ. Grenoble Alpes, IPAG, F-38000 Grenoble (France)
  3. Institut de Radioastronomie Millimétrique, Grenoble (France)
Publication Date:
OSTI Identifier:
22522452
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 804; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CYANIDES; DENSITY; DETECTION; ELEMENT ABUNDANCE; ETHANOL; FORMATES; LUMINOSITY; MASS; METHANOL; METHYL ETHER; MOLECULES; PROTOSTARS; RESOLUTION; STAR EVOLUTION; STARS; TELESCOPES

Citation Formats

Taquet, Vianney, Charnley, Steven B., López-Sepulcre, Ana, Ceccarelli, Cecilia, Kahane, Claudine, and Neri, Roberto, E-mail: taquet@strw.leidenuniv.nl. CONSTRAINING THE ABUNDANCES OF COMPLEX ORGANICS IN THE INNER REGIONS OF SOLAR-TYPE PROTOSTARS. United States: N. p., 2015. Web. doi:10.1088/0004-637X/804/2/81.
Taquet, Vianney, Charnley, Steven B., López-Sepulcre, Ana, Ceccarelli, Cecilia, Kahane, Claudine, & Neri, Roberto, E-mail: taquet@strw.leidenuniv.nl. CONSTRAINING THE ABUNDANCES OF COMPLEX ORGANICS IN THE INNER REGIONS OF SOLAR-TYPE PROTOSTARS. United States. doi:10.1088/0004-637X/804/2/81.
Taquet, Vianney, Charnley, Steven B., López-Sepulcre, Ana, Ceccarelli, Cecilia, Kahane, Claudine, and Neri, Roberto, E-mail: taquet@strw.leidenuniv.nl. Sun . "CONSTRAINING THE ABUNDANCES OF COMPLEX ORGANICS IN THE INNER REGIONS OF SOLAR-TYPE PROTOSTARS". United States. doi:10.1088/0004-637X/804/2/81.
@article{osti_22522452,
title = {CONSTRAINING THE ABUNDANCES OF COMPLEX ORGANICS IN THE INNER REGIONS OF SOLAR-TYPE PROTOSTARS},
author = {Taquet, Vianney and Charnley, Steven B. and López-Sepulcre, Ana and Ceccarelli, Cecilia and Kahane, Claudine and Neri, Roberto, E-mail: taquet@strw.leidenuniv.nl},
abstractNote = {The high abundances of Complex Organic Molecules (COMs) with respect to methanol, the most abundant COM, detected toward low-mass protostars, tend to be underpredicted by astrochemical models. This discrepancy might come from the large beam of the single-dish telescopes, encompassing several components of the studied protostar, commonly used to detect COMs. To address this issue, we have carried out multi-line observations of methanol and several COMs toward the two low-mass protostars NGC 1333-IRAS 2A and -IRAS 4A with the Plateau de Bure interferometer at an angular resolution of 2″, resulting in the first multi-line detection of the O-bearing species glycolaldehyde and ethanol and of the N-bearing species ethyl cyanide toward low-mass protostars other than IRAS 16293. The high number of detected transitions from COMs (more than 40 methanol transitions for instance) allowed us to accurately derive the source size of their emission and the COM column densities. The COM abundances with respect to methanol derived toward IRAS 2A and IRAS 4A are slightly, but not substantitally, lower than those derived from previous single-dish observations. The COM abundance ratios do not vary significantly with the protostellar luminosity, over five orders of magnitude, implying that low-mass hot corinos are quite chemically rich as high-mass hot cores. Astrochemical models still underpredict the abundances of key COMs, such as methyl formate or di-methyl ether, suggesting that our understanding of their formation remains incomplete.},
doi = {10.1088/0004-637X/804/2/81},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 804,
place = {United States},
year = {2015},
month = {5}
}