1. Chemical evolution of HC3N（乙炔腈） in dense molecular clouds
喻耐平
2019
国家天文台

2. Contents
Background
Data & Analysis
Chemical clock
Summary

3. Background
Carbon-chain species: ~40%
HC2n+1N

4. Background (Yu et al. 2016 ApJ)
“This work adds significant new insights of the chemistry in high-mass star-forming regions…, using a fairly good strategy.”

5. Data & Analysis
MALT90
N2H+ (1-0)

6. Data & Analysis Chemical evolution of N2H+ (2018 昆明): Tdust ~ 27 K
Yu et al ApJ

7. Background
HC3N

8. Data & Analysis
RCW RCW Bubble S36

9. Data & Analysis
N(H2)
Tdust
Abundance map

10. HC3N destroyed by UV photons
Data & Analysis
RCW RCW Bubble S36
HC3N destroyed by UV photons

11. Data & Analysis
W33

12. Data & Analysis Study of low-mass star formation:
gas-gas: CN + C2H2 → HC3N + H
shocks:
Mendoza et al. (2018)

13. HC3N might be a shock origin species.
Data & Analysis
W33
Wing emission
(outflow)
HC3N might be a shock origin species.

14. Chemical clock
C+ → Carbon chain species
Suzuki et al ApJ

15. Chemical clock
Taniguchi et al ApJ:

16. Chemical clock
1. An increase in N(HC3N)
2. A decrease in N(N2H+)

17. Summary (1) HC3N could be destroyed by UV photons;
(2) HC3N might be a shock origin species;
(3) The chemical clock of N(N2H+)/N(HC3N).