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Table 2

Isotopic ratios in comet C/2014 Q2 and C/2012 F6.

Isotopic ratio Molecule Value

Comet C/2012 F6 (Lemmon) Mar.-Apr. 2013

D/H H2O 6.5 ± 1.6 × 10-4
HCN <0.045
12C/13C HCN 124 ± 64 or ≥ 89b
14N/15N HCN 152 ± 72 or ≥ 106b
32S/34S CS 20 ± 5
H2S >3.5

Comet C/2014 Q2 (Lovejoy) Jan. 2015

D/H H2O 1.4 ± 0.4 × 10-4
HCN <0.006
H2S <0.017
H2CO <0.007
12C/13C HCN 109 ± 14
CH3OH >61
14N/15N HCN 145 ± 12
16O/18O H2O 499 ± 24 a
32S/34S CS 24.7 ± 3.5
H2S >7
32S/33S CS >50

Notes.

(a)

From time variable fits of the production rates.

(b)

Based only on the backends with the lowest noise.

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