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Table 2.

Isotopic ratios in IRAS 16293A and B using methyl cyanide and its isotopologues.

Isotopic ratio Source A Source B
12C/13Ca 80 ± 19 67 ± 17
12C/13Ca 67 ± 14 80 ± 20
14N/15N 235 ± 33 250 ± 70
D/H(D1,D0)b 1.5 ± 0.3% 1.2 ± 0.3%
D/H(D2,D0)b 3.0 ± 0.3% 4.0 ± 0.5%



The 12C/13C ratio is derived from the 13CH3CN/CH3CN and CHCN/CH3CN ratios, respectively.


The D/H ratio was derived from the CH2DCN/CH3CN and CHD2CN/CH3CN ratios, respectively, taking into account the statistical correction. With D1 referring to the singly deuterated form, D2 referring to the doubly deuterated form, and D0 referring to the main species.

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