Astrochemical Properties of Planck Cold Clumps

Research output: Contribution to journalArticle

  • External authors:
  • Ken'Ichi Tatematsu
  • Tie Liu
  • Satoshi Ohashi
  • Patricio Sanhueza
  • Quang Nguyen Lu'O'Ng
  • Tomoya Hirota
  • Sheng Yuan Liu
  • Naomi Hirano
  • Minho Choi
  • Miju Kang
  • Mark A. Thompson
  • Yuefang Wu
  • Di Li
  • James Di Francesco
  • Kee Tae Kim
  • Ke Wang
  • Isabelle Ristorcelli
  • Mika Juvela
  • Hiroko Shinnaga
  • Maria Cunningham
  • Masao Saito
  • Jeong Eun Lee
  • L. Viktor Tóth
  • Jinhua He
  • Takeshi Sakai
  • Jungha Kim

Abstract

We observed 13 Planck cold clumps with the James Clerk Maxwell Telescope/SCUBA-2 and with the Nobeyama 45 m radio telescope. The N2H+ distribution obtained with the Nobeyama telescope is quite similar to SCUBA-2 dust distribution. The 82 GHz HC3N, 82 GHz CCS, and 94 GHz CCS emission are often distributed differently with respect to the N2H+ emission. The CCS emission, which is known to be abundant in starless molecular cloud cores, is often very clumpy in the observed targets. We made deep single-pointing observations in DNC, HN13C, N2D+, and cyclic-C3H2 toward nine clumps. The detection rate of N2D+ is 50%. Furthermore, we observed the NH3 emission toward 15 Planck cold clumps to estimate the kinetic temperature, and confirmed that most targets are cold (≲20 K). In two of the starless clumps we observed, the CCS emission is distributed as it surrounds the N2H+ core (chemically evolved gas), which resembles the case of L1544, a prestellar core showing collapse. In addition, we detected both DNC and N2D+. These two clumps are most likely on the verge of star formation. We introduce the chemical evolution factor (CEF) for starless cores to describe the chemical evolutionary stage, and analyze the observed Planck cold clumps.

Bibliographical metadata

Original languageEnglish
Article number12
JournalAstrophysical Journal Supplement Series
Volume228
Issue number2
DOIs
StatePublished - 1 Mar 2017