1. Astrochemical modeling of Planck cold clump G224.4-0.6
葛继兴1, 何金华2,3 & Diego 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
in preparation.

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

3. 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.

4. 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

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

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

7. 4. Chemical models Single-point gas-grain model (ggchem):
reaction network : gas phase, dust surface, accretion and desoprtion.
~ 2000 species 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)

8. 5. Comparison with observations
D model: physical parameters

9. 5. Comparison with observations
D model: the chemical age of G
G224S G224NE
DCCS + DHC3N
DCCS + DHC3N
~3.0e+4 year ~4.5e+4 year

10. Off-center CCS peak ???

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

13. 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

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

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

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

17. Thanks！