Nobeyama molecular line survey of SCUBA-2 cores

DOI

We present the results of a single-pointing survey of 207 dense cores embedded in Planck Galactic Cold Clumps distributed in five different environments ({lambda} Orionis, Orion A, Orion B, the Galactic plane, and high latitudes) to identify dense cores on the verge of star formation for the study of the initial conditions of star formation. We observed these cores in eight molecular lines at 76-94GHz using the Nobeyama 45m telescope. We find that early-type molecules (e.g., CCS) have low detection rates and that late-type molecules (e.g., N_2_H^+^ and c-C_3_H_2_) and deuterated molecules (e.g., N_2_D^+^ and DNC) have high detection rates, suggesting that most of the cores are chemically evolved. The deuterium fraction (D/H) is found to decrease with increasing distance, indicating that it suffers from differential beam dilution between the D/H pair of lines for distant cores (>1kpc). For {lambda} Orionis, Orion A, and Orion B located at similar distances, D/H is not significantly different, suggesting that there is no systematic difference in the observed chemical properties among these three regions. We identify at least eight high-D/H cores in the Orion region and two at high latitudes, which are most likely to be close to the onset of star formation. There is no clear evidence of the evolutionary change in turbulence during the starless phase, suggesting that the dissipation of turbulence is not a major mechanism for the beginning of star formation as judged from observations with a beam size of 0.04pc.

Cone search capability for table J/ApJS/249/33/table1 (Information of 207 SCUBA-2 cores embedded in Planck Galactic Cold Clumps)

Identifier
DOI http://doi.org/10.26093/cds/vizier.22490033
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJS/249/33
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/249/33
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/249/33
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJS/249/33
Provenance
Creator Kim G.; Tatematsu K.; Liu T.; Yi H.-W.; He J.; Hirano N.; Liu S.-Y.,Choi M.; Sanhueza P.; Toth L.V.; Evans Ii N.J.; Feng S.; Juvela M.,Kim K.-T.; Vastel C.; Lee J.-E.; Nguyen Lu'o'ng Q.; Kang M.,Ristorcelli I.; Feher O.; Wu Y.; Ohashi S.; Wang K.; Kandori R.; Hirota T.,Sakai T.; Lu X.; Thompson M.A.; Fuller G.A.; Li D.; Shinnaga H.; Kim J.
Publisher CDS
Publication Year 2022
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Interdisciplinary Astronomy; Interstellar medium; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy