The ALMA Survey of 70 mu m 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 mu m 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 (CS)-C-13 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

The Graduate University for Advanced Studies (SOKENDAI)

National Astronomical Observatory of Japan

Xing Lu

Chinese Academy of Sciences

Chang Won Lee

University of Science and Technology (UST)

Korea Astronomy and Space Science Institute

Qizhou Zhang

Harvard-Smithsonian Center for Astrophysics

Stefano Bovino

University of Concepcion

Giovanni Sabatini

Italian ALMA Regional Centre

Tie Liu

Chinese Academy of Sciences

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

Takeshi Sakai

University of Electro-Communications

Junzhi Wang

Chinese Academy of Sciences

Fei Li

Nanjing University

Andrea 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 2 102

Subject Categories

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Geology

DOI

10.3847/1538-4357/ac94d4

More information

Latest update

11/29/2022