The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VII. Chemistry of Embedded Dense Cores
Journal article, 2022
We present a study of the chemistry toward 294 dense cores in 12 molecular clumps, using data obtained from the ALMA Survey of 70 μm dark High-mass clumps in Early Stages. We identified 97 protostellar cores and 197 prestellar core candidates, based on the detection of outflows and molecular transitions of high upper-energy levels (E u /k > 45 K). The detection rate of the N2D+ emission toward the protostellar cores is 38%, which is higher than 9% for the prestellar cores, indicating that N2D+ does not exclusively trace prestellar cores. The detection rates of the DCO+ emission are 35% for the prestellar cores and 49% for the protostellar cores, which are higher than those for N2D+, implying that DCO+ appears more frequently than N2D+ in both prestellar and protostellar cores. Both the N2D+ and DCO+ abundances appear to decrease from the prestellar to the protostellar stage. The DCN, C2D, and 13CS emission lines are rarely seen in the dense cores of early evolutionary phases. The detection rate of the H2CO emission toward dense cores is 52%, three times higher than that for CH3OH (17%). In addition, the H2CO detection rate, abundance, line intensities, and line widths increase with the core evolutionary status, suggesting that the H2CO line emission is sensitive to protostellar activity.
Author
Shanghuo Li
Korea Astronomy and Space Science Institute
Max Planck Society
Patricio Sanhueza
National Astronomical Observatory of Japan
The Graduate University for Advanced Studies (SOKENDAI)
X. Lu
Shanghai Astronomical Observatory
Chang Won Lee
Korea Astronomy and Space Science Institute
University of Science and Technology (UST)
Q. Zhang
Harvard-Smithsonian Center for Astrophysics
Stefano Bovino
University of Concepcion
Giovanni Sabatini
Istituto di Radioastronomia
Tie Liu
Shanghai Astronomical Observatory
Kee-Tae Kim
Korea Astronomy and Space Science Institute
University of Science and Technology (UST)
Kaho Morii
University of Tokyo
Daniel Tafoya
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Ken’ichi Tatematsu
National Astronomical Observatory of Japan
T. Sakai
University of Electro-Communications
Junzhi Wang
Shanghai Astronomical Observatory
Fei Li
Nanjing University
A. Silva
National Astronomical Observatory of Japan
Natsuko Izumi
Academia Sinica
David Allingham
University of Newcastle
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 939 2 102Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Geology
DOI
10.3847/1538-4357/ac94d4