Astrochemistry Focus and Research on Planck Cold Clumps
  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
N$_2$H$^+$ distribution obtained with the Nobeyama telescope is quite similar
to SCUBA-2 dust distribution. The 82 GHz HC$_3$N, 82 GHz CCS, and 94 GHz CCS
emission are often distributed differently with respect to the N$_2$H$^+$
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, HN$^{13}$C, N$_2$D$^+$, cyclic C$_3$H$_2$
toward nine clumps. The detection rate of N$_2$D$^+$ is 50\%. In two of the
starless clumps observe, the CCS emission is distributed as it surrounds the
N$_2$H$^+$ core (chemically evolved gas), which resembles the case of L1544, a
prestellar core showing collapse. In addition, we detected both DNC and
N$_2$D$^+$. 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.
