Astrochemistry Focus and Research on Planck Cold Clumps

Ken’ichi Tatematsu
(Submitted on 5 Dec 2017)

At the Astrochemistry Focus Group, we discussed what is still missing in our understanding even with new knowledge given at this conference, and what can be done for that within 10 years from now.

Still missing in understanding are UV-photons and cosmic-rays interactions with icy dust grains, Sulphur and Phosphorus chemistry, Metallicity effect, Duration (time) effect, COM formation and destruction, phase transition, dust-gas interface, dust evolution, etc. What we should do are multi-scale high spectral resolution molecular observations, laboratory work, theory, radiative transfer, etc. We need careful modeling without simplifying things. Next, I introduce our research on Planck cold clumps. We observed thirteen 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+, cyclic C3H2 toward nine clumps. The detection rate of N2D+ is 50\%. In two of the starless clumps observe, 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.

Comments:    Proceedings of the Star Formation in Different Environments, ICISE, Quy Nhon, Vietnam, 2016, (eds. D. Johnstone, T. Hoang, F. Nakamura, Q. Nguyen-Luong, and J. T. Tranh Van)
Subjects:    Astrophysics of Galaxies (astro-ph.GA)
Report number:    ICISE/SFDE16/29
Cite as:    arXiv:1712.01421 [astro-ph.GA] (or arXiv:1712.01421v1 [astro-ph.GA] for this version)
Submission history
From: Ken’ichi Tatematsu [via QUANG proxy]
[v1] Tue, 5 Dec 2017 00:06:15 GMT (714kb,D)
https://arxiv.org/abs/1712.01421
Astrochemistry
Astrobiology