HOCN and HNCO abundance ratio in molecular gas can tell us the information of their formation mechanism.We performed high-sensitivity mapping observations of HOCN,HNCO,and HNC^(18)O lines around Sagittarius B2(Sgr B2)...HOCN and HNCO abundance ratio in molecular gas can tell us the information of their formation mechanism.We performed high-sensitivity mapping observations of HOCN,HNCO,and HNC^(18)O lines around Sagittarius B2(Sgr B2)with the IRAM 30 m telescope at the 3 mm wavelength.HNCO 4_(04)-3_(03)and HOCN 4_(04)-3_(03)are used to obtain the abundance ratio of HNCO to HOCN.The ratio of HNCO 4_(04)-3_(03)to HNC^(18)O 4;-3;is used to calculate the optical depth of HNCO 4_(04)-3_(03).The abundance ratio of HOCN and HNCO is observed to range from 0.4%to0.7%toward most positions,which agrees well with the gas-grain model.However,the relative abundance of HOCN is observed to be enhanced toward the direction of Sgr B2(S),with HOCN to HNCO abundance ratio of~0.9%.The reason for that still needs further investigation.Based on the intensity ratio of HNCO and HNC^(18)O lines,we updated the isotopic ratio of;O/;O to be 296±54 in Sgr B2.展开更多
基金supported by the National Natural Science Foundation of China(11773054 and U1731237)supported by the international partnership program of Chinese Academy of Sciences through Grant No.114231KYSB20200009。
文摘HOCN and HNCO abundance ratio in molecular gas can tell us the information of their formation mechanism.We performed high-sensitivity mapping observations of HOCN,HNCO,and HNC^(18)O lines around Sagittarius B2(Sgr B2)with the IRAM 30 m telescope at the 3 mm wavelength.HNCO 4_(04)-3_(03)and HOCN 4_(04)-3_(03)are used to obtain the abundance ratio of HNCO to HOCN.The ratio of HNCO 4_(04)-3_(03)to HNC^(18)O 4;-3;is used to calculate the optical depth of HNCO 4_(04)-3_(03).The abundance ratio of HOCN and HNCO is observed to range from 0.4%to0.7%toward most positions,which agrees well with the gas-grain model.However,the relative abundance of HOCN is observed to be enhanced toward the direction of Sgr B2(S),with HOCN to HNCO abundance ratio of~0.9%.The reason for that still needs further investigation.Based on the intensity ratio of HNCO and HNC^(18)O lines,we updated the isotopic ratio of;O/;O to be 296±54 in Sgr B2.
