Astrochemical modeling of Planck cold clump G224.4-0.6 葛继兴1, 何金华2,3 & Diego Mardones1 @ TOP-SCOPE project 1 智利大学天文系 2 云南天文台 3 中智天文中心 星际物理与化学 昆明 2018-07-29 in preparation. gejixing666@gmail.com

Outline Background Observed molecular distributions in G224.4-0.6 Physical parameters of G224.4-0.6 Chemical models （0-D） Comparison with observations 5.1 1-D model 5.2 2-D model 5.3 0-D model 6. Discussions and conclusions

Planck survey: 13188 Planck cold clumps (Tdust<14K). TOP-SCOPE project TRAO Observations of PGCCs (TOP) TRAO 14 m telescope 2000 PGCC sources (blue dots) selected for TOP To find CO dense clumps, to investigate the roles of turbulence, magnetic fields and gravity in structure formation SCUBA-2 Continuum Observations of Pre-protostellar Evolution (SCOPE) East Asia Observatory (EAO) JCMT 15m 850um 1000 PGCC sources (magenta dots) selected for SCOPE to obtain a census of dense clumps distributed in widely different environments; to study the roles of filaments in dense core formation; to investigate dust properties; and to detect rare populations of dense clumps Liu … Ge … 2018, ApJS.

Joint surveys and follow-up observations e.g., SMT 10-m, KVN 21-m, NRO 45-m, & SMA (Liu et al. 2016; Tatematsu et al. 2017). 13 PGCCs, NH3, HNC,HC3N, CCS, N2H+, N2D+ (Tatematsu et al. 2017) Chemical Evolution Factor (CEF) Deuterium fractionation

2. Observed molecular distributions in G224.4-0.6 CCS HC3N N2H+ CCS peak HC3N peak N2H+ peak

3. Physical parameters of G224.4-0.6 Plummer-like function (Plummer 1911).

4. Chemical models Single-point gas-grain model (ggchem): reaction network : gas phase, dust surface, accretion and desoprtion. ~ 2000 species + 50000 reactions (13C- and D-bearing species) Physical parameters: density, extinction, gas (dust) temperature and interstellar radiation field. + + gas temperature 15K (Tatematsu et al., 2017) dust temperature 11K (Planck 2016)

5. Comparison with observations 5.1 1-D model: physical parameters

5. Comparison with observations 5.1 1-D model: the chemical age of G224.4-0.6 G224S G224NE DCCS + DHC3N DCCS + DHC3N ~3.0e+4 year ~4.5e+4 year

Off-center CCS peak ???

5. Comparison with observations 5.2 2-D model: the off-center local peak of CCS

CCS and HC3N peaks occur at 4e4 year because the depletion. t(1e6 cm-3)~1.7e4 year  C1 & C2 t(5e5 cm-3)~3.5e4 year  C3 t(1e5 cm-3)~1.7e5 year  P N2H+ distribution is consistent with observations. But it’s not a good tracer of the chemical age . Ring-like distributions of CCS and HC3N -> High resolution observations Center: depletion Edge: C+ + CCS -> C2S+ + C

5. Comparison with observations 5.3 0-D model: abundance and abundance ratios G224NE/G224S: 106 cm-3, 90 mag G224NE G224S

6. Discussions and conclusions Marsh et al., 2017 Density 1e4, 1e5, 1e6 Temperature 10, 20 K Extinction

6. Discussions and conclusions ??? External radiation field + Dust-to-gas mass ratio depletion Chemical age ~ 3e4-5e4 year Liseau et al. 2015.

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